METHODS AND APPARATUS FOR COLOR CALIBRATION AND VERIFICATION

Abstract: Methods and apparatus for calibrating a color measuring instrument with a color standard and verifying the color standard and calibration are provided. One method includes providing a color standard having a surface with at least two different colors (preferably arranged for a simultaneous color measurement), calibrating the instrument, and verifying that said color standard is an authorized color standard of a predetermined specification and that the calibration of the color measuring instrument has achieved predetermined specified results. Some of the provided methods and apparatus use a photosensitive portion of the color standard that changes color in a known way when exposed to a predetermined dose of light. Various color standards for use with this invention are provided.

Description: METHODS AND APPARATUS FOR COLOR CALIBRATION AND VERIFICATION Background of the Invention This invention relates to color measuring instruments and, in particular, to methods and apparatus for calibrating and verifying the calibration of color measuring instruments that are suitable for measuring the color of a surface, including human skin. It is well known that color measuring instruments, such as colorimeters and spectrophotometers, can be used to measure the color of surfaces for a variety of useful applications . For example, Macfarlane et al . U.S. Patent No. 5,313,267 describes a method and instrument for selecting personal compatible colors using a color measuring device. Also, PCT Publication No. WO 96/41140 describes methods and apparatus for determining the condition of a test subject based on color by using a color measuring instrument to detect change in a color factor indicative of a condition such as a disease, spoilage, ageing, etc. In particular, those methods and apparatus can be used to detect a medical condition known as hyperbilirubinemia by measuring skin color. However, in order to ensure that the skin . color measurements are accurate, they are usually preceded by conventional calibration and optionally conventional verification techniques. Such calibration can be performed by measuring a single color standard of predetermined coloration having premeasured color measurement value (s) and comparing the measurement value (s) with the premeasured value (s) to see that they are substantially the same. Once calibrated, the instrument is normally prepared to perform accurate color measurements producing color measurement value (s) that characterize the color of an unknown sample. Additionally, further subsequent verification against a color standard that is different than that of the color standard used during calibration can help to ensure that the standard used to calibrate the color measuring instrument was an accurate and authorized color standard for its intended calibration and that calibration was performed according to predetermined specifications . When color measuring instruments are used for medical applications, such as when they are used to detect abnormal medical conditions (including hyperbilirubinemia) , the accuracy of the color standard used for calibration and verification is critical. However, color standards may be inaccurate because they have been inadvertently scratched and/or soiled by previous users or because they have become discolored, or faded, from atmospheric or electro-magnetic radiation exposure. Furthermore, another reason for inaccuracy of the color standard includes poor quality control at the site where the color standard is manufactured. Poor quality control at the manufacturing site may yield unacceptable variability in coloration of a color standard (even though the color standard is new and unused) . Moreover, color . standards from unauthorized manufacturing sites may be mislabeled. Furthermore, when a color measuring instrument is used to determine a medical condition, a portion of the instrument usually makes an optical seal on the surface of the patient's skin. In order to make the seal, however, that portion of the color measuring instrument normally makes physical contact with the skin. A disadvantage of such contact is that the contacting surface of the instrument could transfer germs between successive patients when a single color measuring instrument is used to make such measurements . In view of the foregoing, it is an object of this invention to provide sanitary methods and apparatus for making color measurements of human skin among other uses for such an invention, such as measuring laboratory specimens . It is yet another object of this invention to provide improved color calibration and verification methods and apparatus that can detect inaccurate or unauthorized color standards and inaccurate calibration of color measuring instruments. It is another object of this invention to provide methods and apparatus for safely measuring medical conditions without the risk of germ transfer. Summary of the Invention These and other objects of the invention are accomplished in accordance with the principles of the invention by providing methods and apparatus to ensure proper calibration and verification of calibration of color measuring instruments . As used herein, the term "calibration" includes both conventional calibration and standardization techniques as defined by Standard Terminology of Appearance (ASTM definitions) . Conventional color calibration is the finding and elimination of systematic errors of a color measurement instrument scale or method of measurement by use of material standard and techniques traceable to an authorized national or international measurement system. Standardization is the process of adjusting the instrument output to correspond to a previously established calibration using one or more specimens or reference materials. A method of calibrating a color measuring instrument with a color standard and verifying the color standard and the calibration according to this invention can include the following steps. First, a color standard having a surface with at least two different colors is provided. Second, the color measuring instrument is calibrated. And third, the calibration of the color measuring instrument is verified. The color standard used in a preferred embodiment is one having at least two different colors arranged for simultaneous color measurement to sequentially calibrate a color measuring instrument with first predetermined color measurement value (s) of the color standard and verify the calibration with at least second and different predetermined color measurement value (s) of the color standard, the color calibration and verification apparatus includes variance means to provide at least such first and second different color measurement values, the variance means being selected from the group consisting of : (1) sequential inclusion and exclusion of the predetermined color measurement value (s) of the predetermined color measurement value (s) of a portion of said colors, (2) sequential exclusion and inclusion of the predetermined color measurement value (s) of the predetermined color measurement value (s) of a portion of said colors, and (3) sequential unexposure and exposure of photosensitive paper or material which provides at least one of said colors or portion of said colors . The color standard used in another preferred embodiment of this invention has a first color that is characterized by a first predetermined coloration having premeasured color measurement value (s) and a second color that is characterized by a second predetermined coloration having premeasured color measurement value (s). The color standard used in calibrating and verifying a color measuring instrument can include: (1) a first predetermined coloration's premeasured color measurement value (s), (2) a second predetermined coloration's premeasured color measurement value (s), or (3) any combination of the first and the second predetermined coloration's premeasured color measurement value (s) . Any portion, region, or section of the color standard can be photosensitive so that its color changes in a known way when exposed to a predetermined dose of light. The surface of the color standard can be a single surface with two colors or, in another preferred embodiment, can be two separate surfaces with two respective colors. For example, a first color which is characterized by a first predetermined coloration having premeasured color measurement value (s) can be disposed on a first surface of the color standard and a second color (which is characterized by a second predetermined coloration having premeasured color measurement value (s) ) can be disposed on a second surface of the color standard. The second surface can be the opposite side of the first surface. When two or more colors are disposed on a single surface, the colors are preferably arranged for a simultaneous color measurement. A simultaneous color measurement according to this invention includes one color measurement of a single portion having two or more colors . Although the colors are preferably arranged so that a simultaneous color measurement can be made according to this invention, one or more of the colors can be measured separately or in combination. Furthermore, one or more simultaneous color measurements can be performed during a single calibration or verification. Preferably, the color standard used according to this invention is substantially opaque or has a surface against the back of the color standard that is opaque . Suitable color standards for skin color measurements for detecting conditions affecting hyperbilirubinemia can be chosen using skin color categories . Skin color categories are disclosed in Macfarlane et al. U.S. Patent No. 5,671,735, Macfarlane et al. U.S. Patent Application Ser. No. 08/939,462, filed on September 29, 1997, Macfarlane et al . U.S. Patent Application Ser. No. 08/939,588, filed on September 29, 1997, Macfarlane et al. U.S. Patent Application Ser. No. 08/939,784, filed on September 29, 1997, Macfarlane et al . U.S. Patent Application Ser. No. 08/939,232, filed on September 29, 1997, and PCT Publication No. WO 96/41140 (which are hereby incorporated by reference in their entirety herein) . By using combinations of these categories of colors as the colors described on color standard surface for the calibration or verification of the invention herein, it could in some cases provide greater accuracy in measuring the color of skins for detecting abnormal medical conditions, such as hyperbilirubinemia. Suitable color standards for hair color measurements can be chosen using hair color classifications. Hair color classifications are disclosed in Macfarlane et al . U.S. Patent Application Ser. No. 08/657,590, filed June 7, 1996, and PCT Publication No. WO 96/41139 (which are hereby incorporated by reference in their entirety herein) . A color measuring instrument and a calibration and verification apparatus for calibrating and further verifying the calibration are also provided. Brief Description of the Drawings FIG. 1 is a simplified illustrative embodiment of a color measuring instrument being used with a calibration and verification apparatus against a surface of a sample of unknown colorization, in accordance with this invention. FIGS. 2A-2D are planar views of various illustrative embodiments of color standards, in accordance with this invention. FIG. 3 is an exploded perspective view of an illustrative embodiment of a calibration and verification apparatus, in accordance with this invention. FIG. 3 also shows a head of a color measuring instrument on which the apparatus can be mounted. FIG. 4A is an exploded perspective view of another illustrative embodiment of a calibration and verification apparatus, including a variable aperture mask, frame, and color standard, in accordance with this invention. FIG. 4A also shows a head of a color measuring instrument on which the apparatus can be mounted. FIG. 4B is a perspective view of the variable aperture mask and frame shown in FIG. 4A in a "closed" position, in accordance with this invention. FIG. 4C is a perspective view of the variable aperture mask and frame shown in FIG. 4A in an "open" position, in accordance with this invention. FIG. 5A is an exploded perspective view of yet another illustrative embodiment of a calibration and verification apparatus, including another variable aperture mask, frame, and color standard, in accordance with this invention. FIG. 5A also shows a head of a color measuring instrument on which the apparatus can be mounted. FIG. 5B is a perspective view of the variable aperture mask and frame shown in FIG. 5A in a "closed" position, in accordance with this invention. FIG. 5C is a perspective view of the variable aperture mask and frame shown in FIG. 5A in an "open" position, in accordance with this invention. FIG. 6A is a planar view of still another illustrative embodiment of a color standard, in accordance with this invention. FIG. 6B is a planar view of a mask that can be used with the color standard shown in FIG. 6A in accordance with this invention. FIG. 6C is a side view of yet another illustrative embodiment of a calibration and verification apparatus that can be used with the color standard shown in FIG. 6A and the mask shown in FIG. 6B, in accordance with this invention. FIG. 6D is a cross-sectional view of the calibration and verification apparatus taken from line 6D-6D of FIG. 6C, in accordance with this invention. FIG. 6E is a side view of yet another illustrative embodiment of a calibration and verification apparatus that can be used with the color standard shown in FIG. 6A and the mask shown in FIG. 6B, in accordance with this invention. FIG. 6F is a cross-sectional view of the calibration and verification apparatus taken from line 6F-6F of FIG. 6E, in accordance with this invention. FIG. 7A is a side cross-sectional view of yet another illustrative embodiment of a calibration and verification apparatus that can be used in accordance with this invention. FIG. 7B is a cross-sectional view of the calibration and verification apparatus taken from line 7B-7B of FIG. 7A with a mask in a first operable position, in accordance with this invention. FIG. 7C is a cross-sectional view of the calibration and verification apparatus taken from line 7C-7C of FIG. 7A with a mask in a second operable position, in accordance with this invention. FIG. 8 is an exploded perspective view of still another illustrative embodiment of a calibration and verification apparatus, including a frame and a color standard, in accordance with this invention. FIG. 8 also shows a head of a color measuring instrument on which the apparatus can be mounted. FIG. 9 is an exploded perspective view of yet another illustrative embodiment of a calibration and verification apparatus using a photosensitive layer in accordance with this invention. FIG. 9 also shows a head of a color measuring instrument on which the apparatus can be mounted. FIG. 10 is a perspective view of the calibration and verification apparatus shown in FIG. 9 where the apparatus is in an assembled configuration. FIG. 10 also shows a head of a color measuring instrument on which the apparatus can be mounted. FIG. 11 is an exploded perspective view of yet another illustrative embodiment of a calibration and verification apparatus using a photosensitive layer in accordance with this invention. FIG. 11 also shows a head of a color measuring instrument on which the apparatus can be mounted. FIG. 12 is a perspective view of the calibration and verification apparatus shown in FIG. 11 where the apparatus is in an assembled configuration. FIG. 12 also shows a head of a color measuring instrument on which the apparatus can be mounted. FIG. 13 is a cross-sectional side view of yet a further illustrative embodiment of a calibration and verification apparatus using a photosensitive layer in accordance with this invention, where the apparatus is in an assembled configuration. FIG. 14 is a cross-sectional exploded side view of the calibration and verification apparatus shown in FIG. 13. FIG. 15 is a top view, partly in section, of the calibration and verification apparatus shown in FIG. 13. FIG. 16 is a cross-sectional side view of yet a further illustrative embodiment of a calibration and verification apparatus using a photosensitive portion in accordance with this invention, where the apparatus is in an assembled configuration. FIG. 17 is a cross-sectional exploded side view of the calibration and verification apparatus shown in FIG. 16. FIG. 18 is a top view, partly in section, of the calibration and verification apparatus shown in FIG. 16. FIG. 19 is a cross- sectional side view of yet a further illustrative embodiment of a calibration and verification apparatus using a photosensitive layer in accordance with this invention, where the apparatus is in an assembled configuration. FIG. 20 is a cross-sectional exploded side view of the calibration and verification apparatus shown in FIG. 19. FIG. 21 is a top view, partly in section, of the calibration and verification apparatus shown in FIG. 19. Detailed Description of the Preferred Embodiments According to one aspect of this invention, a color calibration and verification apparatus for calibrating and verifying the calibration of a color measuring instrument is provided. In one embodiment, the apparatus includes a color standard having a surface with at least two different colors arranged for a simultaneous color measurement . In another embodiment, the apparatus includes a color standard having a surface with at least a first region and a second region, wherein the first region has a first color characterized by a first predetermined coloration having premeasured color measurement value (s) , and wherein the second region is photosensitive and has a second color characterized by a second predetermined coloration having premeasured color measurement values prior to exposure to light and after exposure to light of a predetermined quantity, and is adequately photosensitive to allow a sufficient change in color by exposure to a predetermined quantity of light for the color measurement instrument to differentiate the color measurement values prior to exposure and after exposure to such light. According to another aspect of this invention, color measuring instruments and methods for calibrating and verifying color measuring instruments are provided. In one embodiment, a method for calibrating a color measuring instrument and verifying the calibration is provided. The method can include: (a) providing a color standard having a substantially opaque surface with at least two different colors arranged for simultaneous color measurement ; (b) sequentially calibrating the instrument with first predetermined color measurement value (s) of the color standard and verifying the calibration with at least second and different predetermined color measurement value (s) of the color standard; (c) providing variance means to provide said first and second different color measurement values, said variance means being selected from the group consisting of: (1) sequential inclusion and exclusion of predetermined color measurement value (s) of a portion of said colors, (2) sequential exclusion and inclusion of predetermined color measurement value (s) of a portion of said colors, and (3) sequential unexposure and exposure of photosensitive paper or material which provides at least one of said colors or region or portion of said colors; (d) calibrating said instrument with said first predetermined color measurement value (s) of the color standard; (e) causing the variance means to provide at least second and different predetermined color measurement value (s) of the color standard; and (f) verifying the calibration of the color measurement instrument with said at least second and different predetermined color measurement value (s) of the color standard. In another embodiment, a method for calibration of a color measuring instrument and verification of the calibration using a color calibration and verification apparatus is provided. An apparatus for use with the method includes: (a) a color standard having a substantially opaque surface with at least two different colors arranged for simultaneous color measurement to sequentially calibrate the instrument with first predetermined color measurement value (s) of the color standard and verify the calibration with at least second and different predetermined color measurement value (s) of the color standard, and (b) variance means to provide first and at least second different color measurement values, the variance means being selected from the group consisting of: (1) sequential inclusion and exclusion of predetermined color measurement value (s) of a portion of the colors, (2) sequential exclusion and inclusion of predetermined color measurement value (s) of the portion of the colors, and (3) sequential unexposure and exposure of photosensitive paper or material which provides at least one of the colors or portion of the colors. The method includes (a) calibrating the instrument with first predetermined color measurement value (s) of the color standard; (b) causing the variance means to provide at least second and different predetermined color measurement value (s) of the color standard; and (c) verifying the calibration of the color measurement instrument with at least second and different predetermined color measurement value (s) of the color standard. The color measuring instrument for use with this method includes: (a) means for calibrating the instrument with first predetermined color measurement value (s) of the color standard; (b) means for causing the variance means to provide at least second and different predetermined color measurement value (s) of the color standard; and (c) means for verifying the calibration of the color measurement instrument with at least second and different predetermined color measurement value (s) of the color standard. According to one aspect of this invention, calibrating can include at least measuring a known and predetermined portion of the color standard to obtain calibration color measurement value (s), and verifying can include at least measuring a second known portion to obtain verification color measurement value (s) . When the first and second known portions are the same, exposing preferably includes exposing at least the second color (i.e., photosensitive region) to a predetermined dose of light such that the calibration color measurement value (s) and the verification color measurement value (s) are different. In another embodiment, the method includes: (1) providing a color standard having a surface with at least two different colors arranged for a simultaneous color measurement; (2) calibrating the instrument; and (3) verifying that the color standard used in calibration is an authorized color standard of the predetermined specification and that the calibration of the color measuring instrument has achieved predetermined specified results. The color measuring instrument for use with this method includes: (1) means for calibrating with the color standard; and (2) means for verifying that the color standard used in calibration is an authorized color standard of the predetermined specification and that the calibration of the color measurement instrument has achieved predetermined specified results . According to another aspect of this invention, another method includes: (1) providing a color standard having a surface with at least a first region and a second region, wherein the first region has a first color characterized by a first predetermined coloration having premeasured color measurement value (s), and wherein the second region is photosensitive; (2) calibrating the instrument with the apparatus; (3) exposing at least the second region to light; and (4) verifying that the color standard used in calibration is an authorized color standard of the predetermined specification and that the calibration of the color measurement instrument has achieved predetermined specified results. The color measuring instrument for use with this method includes: (1) means for calibrating; (2) means for exposing at least the second region to light; and (3) means for verifying that the color standard used in calibration is an authorized color standard of the predetermined specification and that the calibration of the color measurement instrument has achieved predetermined specified results. Either of the above methods can include the following steps: (1) providing a color standard having a surface with at least two different colors, a first of the colors being characterized by a first predetermined coloration having premeasured color measurement value (s) and a second of the colors being characterized by a second predetermined coloration having premeasured color measurement value (s); (2) calibrating the instrument, the calibrating comprising: measuring at least a first known and predetermined portion of the color standard surface to obtain preliminary calibration color measurement value (s), adjusting the instrument output to correspond to previously established calibrations, using the portion of the color standard and remeasuring the portion of the color standard to obtain calibration color measurement value (s) and comparing the calibration color measurement value (s) with a calibration's premeasured color measurement value (s) for the same known and predetermined portion of the color standard surface to ensure that the calibration color measurement value (s) and the calibration's premeasured color measurement value (s) is substantially the same and therefore to ensure that calibration has achieved predetermined specified results; and (3) verifying that the color standard used in calibration is an authorized color standard of the predetermined specification and that the calibration of the color measurement instrument has achieved predetermined specified results, the verifying comprising: measuring at least a second known and predetermined portion of the color standard surface to obtain verification color measurement value (s), and determining that the verification color measurement value (s) is substantially equal to .a verification's premeasured color measurement value (s) for the same known and predetermined portion of the color standard surface. With a color standard having at least two different colors arranged for simultaneous color measurement to sequentially calibrate a color measuring instrument with first predetermined color measurement value (s) of the color standard and verify the calibration with a second and different predetermined color measurement value (s) of the color standard, the color calibration and verification apparatus includes variance means to provide such first and second different color measurement values, the variance means being selected from the group consisting of (1) sequential inclusion and exclusion of at least the predetermined color measurement value (s) of a portion of said colors, (2) sequential exclusion and inclusion of at least the predetermined color measurement value (s) of a portion of said colors, and (3) sequential unexposure and exposure of photosensitive paper or material which provides at least one of said colors or portion of at least one of said colors. FIG. 1 shows a simplified illustrative embodiment of color measuring instrument 10 and calibration and verification apparatus 20 in accordance with this invention. Instrument 10 can be a color measuring instrument such as a colorimeter or a spectrophotometer or other color measuring instrument suitable for measuring the color of a sample surface 30, such as hair, teeth, matter, materials, or human skin. Sensor head 15 is usually at one end of instrument 10. In order to ensure that measurements of such samples are accurate, such measurements are usually preceded by calibration and optionally verification. Calibration is usually performed by measuring a single color standard with known premeasured color measurement value (s) and comparing the measurement value (s) with the premeasured known value (s) to see that they are substantially the same. Once calibrated, the instrument is normally prepared to perform accurate color measurements producing color measurement value (s) that characterize the color of an unknown sample. However, when the calibration of the color measuring instrument is not performed correctly, such as when the color standard used during calibration was inaccurate for the intended calibration results, a subsequent color measurement of a sample with unknown color will be inaccurate. Thus, subsequent verification against a color standard different than that of the color standard used to calibrate can further ensure that the standard used to calibrate the machine was an accurate and authorized color standard for its intended calibration. In accordance with one aspect of this invention, a method of color calibration and verification includes: (1) providing a color standard having a surface with at least two different colors, (2) calibrating a color measuring instrument by measuring one known portion of the color standard surface, including adjusting the instrument output to correspond to previously established calibration, using the color standard and remeasuring the color standard used in calibration to ensure the calibration achieved predetermined specified results and (3) verifying by measuring another known portion of the color standard surface to verify that the color standard used to calibrate is an authorized color standard having predetermined specifications and that the calibration of the color instrument has achieved predetermined specified results. A color standard according to this aspect of the invention has a surface with at least two different colors. A first color is characterized by a first predetermined coloration having premeasured color measurement value (s) . A second color can be characterized by a second predetermined coloration having premeasured color measurement value (s) . The color standard is preferably substantially opaque, or has a back surface that is substantially opaque, with at least two colors that are arranged for a simultaneous color measurement. As used herein, a color measurement value is any coordinate in any predefined color space. Examples of color spaces include, for example, XYZ Tristimulus value space (CIE 1931) , X 10 Yιo z ιo Tristimulus value space (CIE 1964) , Yxy Chromacity coordinate space, L*a*b* space (CIELAB) , L*C*h space, Munsell space, Hunter Lab space, L*u*v* space (CIELUV) , as well as a series of wavelengths, which can be measured in nanometers. Color measurement value (s) can include one or more color measurement values . Premeasured color measurement value (s) consist of color measurement value (s) that were obtained by measuring the color of a known portion of a color standard surface of specified predetermined coloration with a first calibrated color measuring instrument prior to using such color standard to calibrate a second color measuring instrument for measuring the color of samples . A predetermined coloration's calibration's premeasured color measurement value (s) can be: (1) the first predetermined coloration's premeasured color measurement value (s), (2) the second predetermined coloration's premeasured color measurement value (s),. or (3) any combination of the first and the second predetermined coloration's premeasured color measurement value (s) . A predetermined coloration's calibration's premeasured color measurement value (s) can consist of color measurement value (s) that were obtained by measuring the color of a first known portion of a color standard surface of specified predetermined coloration with the first calibrated color measuring instrument prior to using the color standard to calibrate the second color measuring instrument for measuring the color of samples . A predetermined coloration's verification's premeasured color measurement value (s) can be: (1) the first predetermined coloration's premeasured color measurement value (s), (2) the second predetermined coloration's premeasured color measurement value (s), or (3) any combination of the first and the second predetermined coloration's premeasured color measurement value (s) . A predetermined coloration's verification's premeasured color measurement value (s) can consist of color measurement value (s) that were obtained by measuring the color of a second known portion of a color standard surface of specified predetermined coloration with the first calibrated color measuring instrument prior to using the color standard to calibrate the second color measuring instrument for measuring the color of samples . After a color standard of specified predetermined coloration is provided in the first step, the color measuring instrument is preferably calibrated according to the principles of this invention. As used herein, the term "calibration" includes both conventional calibration and standardization techniques as defined by Standard Terminology of Appearance (ASTM definitions) . Conventional color calibration is the finding and elimination of systematic errors of a color measuring instrument scale or method of measurement by use of material standards and techniques traceable to an authorized national or international measurement system. Standardization is the process of adjusting the instrument output to correspond to a previously established calibration using one or more specimens or reference materials . According to this invention, calibration includes (1) providing a color standard of predetermined specified coloration, (2) measuring at least a first known and predetermined portion of the color standard surface to obtain preliminary calibration color measurement value (s), adjusting the instrument output to correspond to previously established calibration, using the color standard and remeasuring the color standard to obtain calibration color measurement value (s), and (3) comparing the calibration color measurement value (s) (or calculated color measurement value (s) of a different color index, which are calculated from the color measurement value (ε) ) with calibration's premeasured color measurement value (s) for the same known and predetermined portion of the color standard surface to ensure that the calibration color measurement value (s) and the calibration's premeasured color measurement value (s) are substantially the same and therefore to ensure that calibration has achieved predetermined specified results. After the color measuring instrument is calibrated using a first known portion of the color standard surface, a second known portion of the color standard surface is used to verify that the color standard used in the calibration is an authorized color standard of predetermined specification and that the calibration of the color measuring instrument has achieved predetermined specified results. According to this invention, verifying includes (1) measuring at least a second known and predetermined portion of the color standard surface to obtain verification color measurement value (s), and (2) determining that the verification color measurement value (s) (or calculated verification color measurement value (s) of a different color index, which are calculated from the verification color measurement value (s) ) is substantially equal to the verification's premeasured color measurement value (s) for the same know and predetermined portion of the color standard surface. When the verification color measurement value (s) is substantially equal to a verification's premeasured color measurement value (s), it can be determined that the calibration achieved the predetermined specified results and that the color standard used for calibration and for verification was (a) the predetermined color standard specified for calibration and verification and (b) authorized. The first and second colors of predetermined coloration on the color standard surface can be disposed on that surface in a known ratio of surface areas. As used herein, a "known ratio of surface areas" is any ratio of surface areas such that a measurement of a known portion of that surface corresponds to a known and predetermined coloration having premeasured color measurement value (s) . This means that the ratio of a first surface area on which the first color of predetermined coloration is disposed to a second surface area on which the second color of predetermined coloration is disposed is predetermined and known. That known ratio can be uniform over the standard surface or it can vary over the surface, such as radially, in a known fashion. Alternatively, the two colors of predetermined coloration can be disposed on the color standard surface in a known configuration. As used herein, a "known configuration" is any arrangement of colors such that a measurement of a known portion of the color standard surface corresponds to a known and predetermined coloration having premeasured color measurement value (s). A known ratio or configuration permits a variety of calibration and verification methods according to this invention. FIGS. 2A-2D show four embodiments of a color standard with at least two different colors of predetermined coloration according to this invention. FIG. 2A shows color standard surface 205 having a first color of predetermined coloration disposed on central portion 210 of surface 205 and a second color of predetermined coloration disposed on outer portion 215, which is disposed radially outside central portion 210. Preferably, portions 210 and 215 are disposed in a radially symmetric fashion, as shown in FIG. 2A. FIG. 2B shows color standard surface 220 having a first color of predetermined coloration disposed on semicircular portion 225 of surface 220 and a second color of predetermined coloration disposed on adjacent semi- circular portion 230 of surface 220. FIG. 2C shows color standard surface 235 having a first color of predetermined coloration disposed on slices 240 and a second color of predetermined coloration disposed on slices 245 of surface 235. A color standard in accordance with this invention can have three or more colors of predetermined coloration, as shown in FIG. 2D. Color standard 250 of FIG. 2D has a first color of predetermined coloration disposed on a central portion 255, a second color of predetermined coloration disposed on portion 260 that is radially outside portion 255, a third color of predetermined coloration disposed on portion 265 that is radially outside portion 260, and portion 270 that is radially outside portion 265. Although color standard 250 shows four different colors of predetermined coloration, a person of ordinary skill in the art would understand that any number of colors of predetermined coloration can be disposed on surface 250 in accordance with this invention. Also, the colors of predetermined coloration can be disposed on the surface of a color standard in a substantially random fashion, as long as within that random disposition of colors of predetermined coloration each color or gradation of color has a predetermined coloration of premeasured color measurement value (s) for subsequent use in calibration and verification. A common feature of the color standards shown in FIGS. 2A-2D is that they all have predetermined and known color configurations so that a measurement of a known portion of that surface will correspond to known color of predetermined coloration having premeasured color measurement value (s) . According to one aspect of the invention, the two different colors on the color standard can differ only by a single premeasured color measurement value, such as when the predetermined coloration's premeasured color measurement valu (s) are measured in CIE Hunter Lab space (1948) and only the lightness color measurement value L is different. In this case, and . according to this invention, the two colors would be considered to have different premeasured color measurement value (s), as long as the value of L differed, preferably by at least 3 points. One method of achieving a very high L value is by providing a high gloss finish to a region of the color standard. In fact, when the high gloss finish is applied to a region of the color standard, the L value that corresponds to that region can be extremely large (greater than 80 or 90 points) . However, such high gloss finishes also tend to strongly affect (usually increase) the value of the other premeasured color measurement value (s), that is the a and b values. Therefore, in order to make a color measurement of a portion of a color standard having a high L value and relatively unaffected (or low) a and b values, that portion, which can be measured during calibration and/or verification, must include a region having at least one color with a large L value (e.g., a value greater than about 80 points, and preferably greater than about 90 points) and a second color with a relatively small L value and substantially unaffected (e.g., low) a and b values. Thus, in accordance with one aspect of the present invention, calibration and verification can be performed according to this invention by using a color standard with two different colors, a first of which has a high gloss finish and a second of which has a matte, a low gloss (or no gloss) finish. In an unauthorized color standard on which the high gloss finish was provided over the whole known portion, the a and b values would necessarily be large. Thus, if a color measuring instrument was programmed to only calibrate and verify with a high L value and low a and b values, non-authorized color standards could be detected and rejected according to this invention. It should be clear, however, that while this aspect of the invention is described in terms of CIE Hunter Lab space (1948) , any color coordinates of any color index can be used to describe the colorization of a color standard in accordance with this invention. Calibration according to this invention can be performed by measuring any known and predetermined portion of the color standard surface. Therefore, a calibration measurement can include measuring a known and predetermined portion of the standard surface on which a single color of predetermined coloration is disposed, two colors of predetermined coloration are disposed, or three or more colors of predetermined coloration are disposed, as long as that portion corresponds to a known color of predetermined coloration having premeasured color measurement value (s) . In accordance with this invention, calibration can be performed using a color calibration and verification apparatus. FIG. 3 shows an illustrative embodiment of color calibration and verification apparatus 300. Apparatus 300 includes mask 310, frame 320, and color standard 330. Color standard 330 is removably fastened to frame 320. Color standard 330 can have tab portion 331 for a user to grasp when removal of color standard 330 is desired. Mask 310 is mounted, preferably removably mounted, between color measuring instrument sensor head 340 and color standard 330. Mask 310 can also have tab portion 311 for a user to grasp when removal of mask 310 is desired. Also, frame 320 can itself act as a mask to some degree . During calibration with apparatus 300, calibration color measurement value (s) can be obtained by measuring a first known portion of color standard 330. In FIG. 3, the first color of predetermined coloration is disposed centrally on standard 330 and the second color of predetermined coloration is disposed on an annular region radially outside the central region of standard 330. The shape, size, and position of aperture 312 of mask 310 determines the first known portion measured during calibration. That portion can include all of the first color of predetermined coloration, part of the first color of predetermined coloration, or none of the first color of predetermined coloration. As shown in FIG. 3, however, mask 310 blocks the outer annular region so that first known portion 332 of standard 330 is measured alone. When aperture 312 is made larger, the first known portion includes all of the central region characterized by the first color of predetermined coloration and part of the annular region characterized by the second color of predetermined coloration. When aperture 312 is made smaller than the central region (i.e., surface area on which the first color is disposed) , only a part of the central region is measured and none of the annular region is measured. Therefore, the regions that are characterized by different colors can be arranged so that they can be simultaneously measured. However, such an arrangement does not mean that every color measurement includes two or more different colors . After calibration is performed using calibration and verification apparatus 300 shown in FIG. 3, the calibration and the color standard can be verified after removing mask 310. Mask 310 can be removed from apparatus 300 by any convenient method, including grasping and then pulling tab portion 311 of mask 310 until mask 310 no longer blocks light from entering the color measuring instrument . Alternatively, mask 310 could be removed by (1) unfastening apparatus 300 from color measuring instrument head 340 to expose mask 310, (2) pulling tab portion 311 of mask 310 until mask 310 is removed from apparatus 300, and (3) replacing apparatus 300 on color measuring instrument head 340. After mask 310 is removed, the second known portion of color standard 330 includes substantially the entire color standard surface, including all of first known portion 332. In particular, second known portion 334 would include a surface on which the first and second colors of predetermined coloration are disposed. Second known portion 334, which is used during verification, can be any portion of the standard surface, such as a portion that includes first known portion 332. Like calibration, verification can be performed by measuring any known portion of the color standard surface. As described more fully below, first known portion 332 and second known portion 334 can correspond to the same surface area, such as when at least one of the two colors are photosensitive. Therefore, a verification measurement (or alternatively a calibration measurement) can include measuring a known and predetermined portion of the standard surface on which a single color of predetermined coloration is disposed, two colors of predetermined coloration are disposed, or three or more colors of predetermined coloration are disposed, as long as that known portion corresponds to known color of predetermined coloration having premeasured color measurement value (s) . When two or more colors are used, they are preferably arranged for one or more simultaneous color measurements. After calibration is performed using . calibration and verification apparatus 300 shown in FIG. 3, the calibration and the color standard may be verified after removing mask 310. Then, the second known portion of color standard 330 would include substantially the entire color standard surface including first known portion 332 and would be a portion of the color standard surface on which the first color of predetermined coloration and the second color of predetermined coloration are disposed. According to another embodiment of this invention, the aperture of a mask can have a variable size. For example, as shown in FIGS. 4A-4C, calibration and verification apparatus 400 includes mask 410, frame 420, and color standard 430. Color standard 430 (shown in FIG. 4A) is similar to color standard 205, shown in FIG. 2A. Color standard 430 is preferably fastened to frame 420 so that its calibration and verification surface faces color measuring instrument sensor head 440. Color standard 430 can have tab portion 431 for a user to grasp when color standard removal is desired. Mask 410 is mounted between head 440 and color standard 430 and can include a plurality of opaque elements 412 that can move relative to each other to change the diameter of central aperture 422 in order to mask a variable portion of color standard 430 (mask 410 is sometimes referred to as an iris) . Mask 410 preferably has at least two operable positions determined by the relative positions of opaque elements 412, but can have more depending on the number of individual calibration and verification measurements desired. FIG. 4B shows frame 420 and mask 410 in a first operable position where mask 410 masks a radially outer part of the color standard surface. In that position, only first known portion 432 is measurable. FIG. 4C shows mask 410 in a second operable position, in which case only a small outer part of the color standard surface is masked. In that case, second known portion 434 is a portion that includes first portion 432 plus a part of the previously masked surface (an adjacent portion radially outside first known portion 432) . When mask 410 is in a predetermined intermediate position (not shown) between the first and second operable positions, a predetermined combination of colors of predetermined coloration is measurable. Of course, the color configuration of the color standard can be any known configuration and need not be the particular standard shown in FIG. 4A. FIGS. 5A-5C show another calibration and verification instrument 500, which includes mask 510 (including mask elements 510a and 510b) , frame 520, and color standard 530. Color standard 530 shown in FIG. 5 is again similar to color standard 220 shown in FIG. 2B, however that color standard can have any known color configuration of predetermined coloration in accordance with this invention. Color standard 530 is fastened to frame 520 so that the color standard surface faces color measuring instrument sensor head 540. Color standard 530 can have tab portion 531 for a user to grasp when it is desired to remove standard 530 from frame 520 to measure a sample of color. Mask elements 510a and 510b can be mounted in annular frame 520 and between head 540 and color standard 530. Preferably, elements 510a and 510b are slidable relative to frame 520 for masking a desired portion of the surface of standard 530. Mask elements 510a and 510b can also have respective tabs 511a and 511b so that a user can slide each of the mask elements into at least two operable positions (including a completely removed position) , but can have more than two positions depending on the number of individual calibration and verification measurements desired. For example, FIGS. 5B and 5C show mask elements in "closed" and "open" operable positions, respectively. In the closed position, semicircular mask elements form a circle and substantially block outer annular region 535 of the standard, thereby masking first known portion 532 measurable. When mask 510 is in the open position (shown in FIG. 5C) second known portion 534, which includes first known portion 532 and at least some of the previously blocked outer annular region 535 of color standard 530, is measurable. As described above, mask 510 can be used in a predetermined intermediate position between the first and second operable positions so that a predetermined combination of colors of predetermined coloration on the color standard surface is measurable. In another embodiment according to this invention, a color standard can have a plurality of portions that can be measured during calibration and/or verification. When used to calibrate, the measurable portion on the color standard surface is referred to as a first known portion. When used to verify, the measurable portion is referred to as a second known portion. FIG. 6A shows color standard 600, which includes five regions 602, 604, 606, 608, and 610 with different colors disposed thereon. A first known portion, then, can be any of these five regions or, depending on the mask used and its relative position, a predetermined combination of these regions. Similarly, a second known portion- can be any of the regions or a predetermined combination of these regions . Any of the five regions can be photosensitive, as described more fully below. FIG. 6B shows an illustrative embodiment of a mask that can be used in combination with color standard 600 is mask 620. Mask 620 is preferably substantially flat and has aperture 622. Mask 620 can be constructed with any material that is opaque to visible wavelengths of light, and is preferably black. A first known portion, or calibration portion, of standard 600 can be selected by adjusting the relative position between color standard 600 and mask 620. Adjusting the relative position can involve rotating color standard 600 or mask 620 while the other is fixed. For example, FIGS. 6C and 6D show calibration and verification apparatus 630 in which color standard 600 is rotatable and mask 620 is fixed. Apparatus 630 can therefore include color standard 600, mask 620, and frame 632. Frame 632 is mountable to sensor head 640 of a color measuring instrument (not shown) and color standard 600 is fastened to movable frame element 633 such that the surface of color standard 600 faces a light detector, or sensor, in instrument head 640. The desired position of standard 600 can be selected by rotating frame element 633, such as by moving handle 634, which is fixed to movable element 633. In addition to rotating color standard in order to define different known portions of color standard 600 for measurement, mask 620 can be removed entirely from apparatus 630, in which case the known portion would include substantially the entire surface of color standard 600. Mask 620 can be removed by grasping and pulling a tab portion (not shown) of mask 620 and can be performed while apparatus 630 is temporarily removed from instrument head 640. After calibration and verification, standard 600 should be completely removed from movable element 633 by peeling standard 600 away from element 633 by grasping and pulling tab portion 601. Standard 600 can be fastened to frame 633 with adhesive so that standard 600 is destroyed when standard 600 is removed from frame element 633, thereby ensuring that an unexposed standard will be used for any subsequent calibration or verification. After color standard 600 is removed from frame 633, frame 633 remains mounted to head 640 of the color measuring instrument so that color measuring instrument is ready for measuring a sample with unknown coloration, such as human skin. When standard 600 is removed, a sanitary surface (rim 635) of frame 632 is preferably exposed. That sanitary surface of rim 635 can then be placed directly on the unknown surface (e.g., human skin) during a subsequent color measurement . This sanitary feature is especially useful in the medical field where a sanitary surface reduces the possibility of transmitting germs from one patient to another. Mask 620 is preferably removed before measuring the color of a sample of unknown coloration so that a large surface area is available for the subsequent measurement. In an alternative embodiment, FIGS. 6E and 6F show calibration and verification apparatus 650 in which color standard 600 is fixed and mask 620 is rotatable. Apparatus 650 can therefore include color standard 600, mask 620, and frame 652. Frame 652 is mountable to a sensor head 640 of a color measuring instrument (not shown) and color standard 600 is fastened to fixed frame element 653 such that the surface of color standard 600 faces a light detector, or sensor, in instrument head 640. In contrast to apparatus 630, the position of mask 620 in apparatus 650 can be selected by rotation of mask 620, such as by moving mask handle 654, which is fixed to element 653. Regardless of the particular apparatus used, it should be clear to a person of ordinary skill in the art that multiple portions can be selected on color standard 600 for calibration and verification in accordance with this invention. After calibration and verification and in accordance with the sanitary aspect of this invention, standard 600 should be removed from movable element 633 by peeling standard 600 away from element 633 by grasping and pulling tab portion 601. When standard 600 is removed, a sanitary surface (rim 655) of frame 652 is preferably exposed. Preferably, mask 620 should also be removed before measuring the colorization of a sample of unknown colorization in order to maximize the measurable surface area of the sample . According to another embodiment of this invention, FIG. 7 shows calibration and verification apparatus 700. Instrument 700 includes mask 710, frame 720, and color standard 730. Color standard 730 is similar to color standard 220 shown in FIG. 2B, except that standard 730 is substantially square. Any of the colors disposed on color standard 730 can be photosensitive, as described more fully below. Color standard 730 is fastened to frame 720 so that its calibration and verification surface face color measuring instrument sensor head 740. Color standard 730 can have tab portion 731 for a user to grasp when standard removal is desired. Mask 710 can be slidably mounted between head 740 and color standard 730. Accordingly, mask 711 can also have handle portion 711 to (1) facilitate changing the position of mask 710 between calibration and verification and/or (2) to remove mask 711 from frame 720 before measuring the color of an unknown sample. Alternatively, handle portion 712 of mask 710 can also be used to remove mask 710 from frame 720. FIG. 7B shows mask 710 in a first operable position where mask 710 masks first known portion 732 and second known portion 734 is measurable. When mask 710 is in a second operable position, as shown in FIG. 7C, second known portion 734 is masked and first known portion 732 is measurable. When mask 710 is in a predetermined intermediate position between the first and second operable positions, a predetermined combination of colors of predetermined coloration (e.g., colors on first and second portions 732 and 734) is measurable. The physical masking techniques described above can be necessary when the first and second known portions of the color standard would otherwise simultaneously be exposed for a color measurement without a mask. When only one of the known portions is exposed for calibration without a mask, no mask may be necessary. However, in order to expose the other known portion of the color standard for verification, that color standard may be physically moved or reoriented between calibration and verification. One example of a color standard with two surfaces is a flat sheet having two opposite sides, each of which has a surface with a predetermined coloration having premeasured color measurement value (s) . In this case the color standard must be flipped or exchanged, respectively, to expose the appropriate surfaces during calibration and verification. Alternatively, the two surfaces could be on physically distinct objects, in which case the object must be flipped or exchanged between calibration and verification. Regardless of whether a mask is used or not, the above-identified procedures for calibrating and verifying according to this invention still apply. In contrast to the actual masking techniques used to calibrate and verify described above, the methods described below involve constructive masking techniques. "Actual" masking involves the physical blocking of light so that either the first known portion or the second known portion is at least partially defined by a physical mask. "Constructive" masking, however, is performed by a color measuring instrument without a physical mask and can be used when the first known portion and the second known portion include the same color or the same combination of colors -- that is, the portions correspond to the same surface area of the color standard. Constructive masking is useful because the color calibration and verification apparatus used in accordance with this aspect of the invention is simple and inexpensive to manufacture. FIG. 8 shows an illustrative embodiment of color calibration and verification apparatus 800 for use with constructive masking methods of this invention. Apparatus 800 includes frame 820 and color standard 830. Color standard 830 is removably fastened to frame 820. As already described above, color standard 830 can have tab portion 831 for easy removal from frame 820. Removal of color standard 830 can involve peeling color standard 830 away from frame 820 where they are attached, such as by pressure or adhesive. As in the case of physical masking procedures, constructive masking requires that the color standard be removed before a color measurement is made on an unknown sample . When calibrating with apparatus 800, calibration color measurement value (s) are obtained by measuring a known portion of color standard 830. Color standard 830 is similar to standard 205 shown in FIG. 2A, but can be any color standard in accordance with this invention. For example, a color standard for use with this aspect of the invention can have a surface with at least two different colors in accordance with this invention -- namely, a first color characterized by a first predetermined coloration having premeasured color measurement value (s) and a second color characterized by a second predetermined coloration having premeasured color measurement value (s) . Another color standard that can be used in accordance with this invention is one having one or more regions having a high gloss finish or that is photosensitive . As shown in FIG. 8, the first known portion measured during calibration can be substantially the entire color standard surface but can also be a predetermined portion of that surface when a mask is used. Of course, frame 820 can to some degree act as a mask itself . When two or more colors are disposed on a single surface, the colors are preferably arranged for one or more simultaneous color measurements, even though a color measurement of a single color alone can also be possible. This means that first known portion 832 and second known portion 834 can be arranged inside the window provided by frame 820. According to this embodiment of the invention, standard 830 can be verified after calibration without changing the portion of the surface being measured. That is, the first known portion and the second known portion refer to the same surface area of color standard 830, which can include the same colors or the same predetermined combination of colors . Calibration is the same according to this aspect of the invention, but verification includes an extra step. The extra step is necessary because in this constructive technique, the second known portion will have verification measurement value (s) that can be different from the verification's premeasured color measurement value (s) . Therefore, in order to verify whether or not the color standard is an authorized standard of predetermined specification and to verify that the calibration of the color measuring instrument is according to a predetermined specification according to this aspect of the invention, computed color measurement values must be calculated based on the verification color measurement value (ε) and those computed values are compared with the verification's premeasured color measurement value (s) . The calculation is simple because the verification's premeasured color measurement value (s) would be related to the verification color meaεurement value (ε) by predetermined differential color meaεurement value (s) . The computed color measurement value (s) can be the εum of or difference between the verification color measurement value (ε) and the predetermined differential color meaεurement value (s) . Therefore, the step of determining that the verification color measurement value (s) iε substantially equal to the verification's premeasured color measurement value (s) can include (1) calculating computed color measurement value (s) based on the verification color meaεurement value (ε) and (2) determining that the computed color measurement value (s) are εubεtantially equal to the verification's premeasured color meaεurement value (s) . As in the case of the phyεical masking techniques described above, the known portion measured during the calibration and verification εtepε in thiε conεtructive masking technique can be any known portion on the standard surface, and can include a first color, a second color, or a predetermined combination of a first color and a second color. When εtandard 830 haε additional colorε diεpoεed thereon, the known portion can include thoεe additional colorε as well. As deεcribed above, the computed color meaεurement value (ε) can be calculated baεed on the verification color meaεurement value (ε) . In one embodiment, the computed color measurement value (s) can be obtained by adding or subtracting predetermined differential color measurement value (s) to the verification color meaεurement value (ε) . For example, when the known portion meaεured during verification iε a portion that consists esεentially of the first color, the predetermined differential color measurement value (s) can be baεed on the verification's premeasured color meaεurement value (s) . If the verification's predetermined coloration's premeasured color meaεurement value (s) correspond to a combination of the first and εecond colorε, then the predetermined differential color measurement value (ε) would simply correspond to the contribution of the second color, that is, the "difference" between the contribution of the first color and the contribution of the combination of the first and second colors . In another embodiment according to thiε invention, the known portion measured during verification is a portion that consiεtε eεsentially of the second color. In that caεe, the predetermined differential color meaεurement value (s) would also be based on the verification' ε premeaεured color meaεurement value (ε). However, if the verification's premeasured color measurement value (ε) correspond to a combination of the first and second colors, then the predetermined differential color meaεurement value (ε) would εimply correεpond to the contribution of the firεt color, that iε, the "difference" between the contribution of the second color and the contribution of the combination of the first and second colors. In a preferred embodiment, the known portion meaεured in the verification εtep includes a predetermined combination of the first color and the εecond color. Then, if the verification' ε premeaεured color meaεurement value (ε) corresponds to a first color, the predetermined differential color measurement value (ε) would simply correspond to the contribution of the εecond color -- the "difference" between the contribution of the first color and the contribution of the predetermined combination of the firεt and εecond colorε . According to another embodiment of this invention, FIGS. 9 and 10 show calibration and verification apparatus 900. FIG. 9 is an exploded perspective view of apparatuε 900 and FIG. 10 iε an aεεembled perεpective view of apparatuε 900. Apparatuε 900 includeε releaεe liner 910, εanitary layer 920, photoεenεitive layer 930, color εtandard 940, and cap 950. Aε diεcusεed more fully below, while release liner 910, sanitary layer 920, and cap 950 are preferred componentε of apparatuε 900, they are optional according to thiε invention. Releaεe liner 910 haε firεt surface 912, which faces downward in FIG. 9, and second surface 914, which faces upward in FIG. 9. Preferably, firεt surface 912 of release liner 910 attacheε to diεtal surface 962 of color measuring inεtrument head 960, which includeε round window 963 through which color meaεurementε are made. Releaεe liner 910 iε preferably optically opaque to prevent a photoεensitive surface of layer 930 from being expoεed to εufficient electromagnetic radiation to expoεe it enough to change itε color εubεtantially before apparatuε 900 is used. Sanitary layer 920 has first εurface 922, which faceε downward in FIG. 9, and εecond εurface 924, which faceε upward in FIG. 9. Sanitary layer 920 haε firεt optically tranεparent aperture 926, such as a hole, for exposing photosenεitive layer 930 and color εtandard 940 when uεed as described below. Second surface 914 of release liner 910 can be attached to firεt surface 922 of sanitary layer 920 with an adhesive, or any other conventional means. It will be appreciated that while release liner 910 and sanitary layer 920 are attached, they can be separated as desired. For example, when liner 910 and layer 920 are attached to each other by an adhesive, they can be separated without deεtroying εanitary layer 920 by simply pulling tab 918 of release liner 910. Photosenεitive layer 930 haε first surface 932, which faces downward in FIG. 9, and second surface 934, which faces upward in FIG. 9. Layer 930 iε preferably mounted so that first surface 932 faces second surface 924 of sanitary layer 920. First surface 932 has at least a firεt photosensitive color disposed thereon. Also, layer 930 has εecond optically tranεparent aperture 936 that has a crosε-εectional area that iε ε aller than the croεε-εectional area of firεt optically transparent aperture 926. Preferably, region 935 of layer 930 changes color in a known way when exposed to a predetermined doεe of light. One example of a photoεenεitive paper that can be uεed in accordance with thiε invention iε εold under the name "polycontraεt 3RC E, " which is available from the Eastman Kodak Company, of Rochester, New York. In this case, the region of photosensitive layer exposed to viεible light will darken a known amount when the it iε exposed to a predetermined dose of light. Color standard 940 has firεt εurface 942, which faceε downward in FIG. 9, and εecond εurface 944, which faceε upward in FIG. 9. Layer 940 iε mounted εo that itε firεt εurface 942 iε facing εecond surface 934 of layer 930. Furthermore, standard 940 iε mounted so that region 946 of first εurface 942 iε adjacent εecond aperture 936. In this way, region 946 can measured through εecond aperture 936 during operation. Region 935 of photoεenεitive layer 930 preferably changes color in a known way when exposed to a predetermined doεe of light, such as a predetermined number of flaεheε of light emitted by a color meaεuring instrument. It will be appreciated that first surface 942 of standard 940 can be attached to second εurface 934 of layer 930 with adhesive. Second surface 924 of sanitary layer 920 can be removably attached to first εurface 942 of layer 930 with adhesive. The εizeε of variouε componentε uεed in accordance with thiε invention are now deεcribed. The area within aperture 926 iε preferably larger than the area within window 963 εo that inner rim 927 of layer 920 doeε not interfere with color meaεurementε . Alεo, the area within aperture 936 is preferably smaller than the area within window 963 to enεure that at leaεt a portion of photoεenεitive region 935 iε expoεed during color measurements . To ensure that a light-tight seal is formed when layer 930 and εtandard 940 are combined, the εurface area of color standard 940 is preferably at least as large as the area within aperture 936. And, to ensure accurate calibration and verification, the surface area of region 946 iε preferably larger than the εurface area of region 935. Optional cap 950 haε inner εurface 952, which faces downward in FIG. 9, and is adapted to subεtantially fit over at leaεt second aperture 936, which further provides an opaque back surface for the color standard. A method according to this invention for calibrating and verifying via calibration and verification apparatus 900 is now described. To some extent the method has already been discuεsed above, so the deεcription here iε somewhat abbreviated. After mounting the apparatus on the inεtrument εo that the firεt surface of the sanitary layer faceε a head of the inεtrument; the method includeε calibrating the inεtrument with the apparatuε; expoεing at leaεt the εecond region with light; and verifying that the color εtandard uεed in calibration is an authorized color standard of the predetermined specification and that the calibration of the color meaεurement inεtrument haε achieved predetermined specified results . When the apparatus 900 includeε releaεe liner 910, the method alεo includeε removing the releaεe liner from the first surface of the sanitary layer before mounting the apparatus . When apparatus 900 is mounted to instrument head 960, it iε preferably temporarily attached, such as via an adhesive or by some other fastening meanε, εuch as a clip. Regardless of the particular fastening means used to attach apparatus 900 to head 960, the individual layers should be easily removable as described herein. During the calibrating εtep, unexpoεed color meaεurement value (s) of a first known portion, including the photosenεitive region, is determined. As used herein, unexposed color measurement value (s) iε the color measurement value (s) that characterizeε the portion before being expoεed to a εufficient doεe of electromagnetic energy to expoεe it and change itε color εubstantially in the exposing step. In the expoεing step, the known dose of electromagnetic energy can be provided by one or more flasheε emitted by the color meaεuring instrument . Color measurements can be made at any time during the calibration and verification procedure, including after any number of flasheε, aε a further check that the color εtandard being uεed iε unexpoεed. In the verifying step, exposed color meaεurement value (ε) of a εecond known portion is determined. The second known portion can be identical to the first known portion. Aε used herein, exposed color measurement value (s) iε the color meaεurement value (ε) that characterizeε the color of the second known portion after being exposed to sufficient electromagnetic energy in the exposing step to expose it and substantially change its color. If it is determined that the color standard being used to calibrate a color measuring instrument is unexposed, the instrument can be programmed to continue the calibration and verification procedure. On the other hand, if it iε determined that the color εtandard being used to calibrate a color meaεuring instrument has been exposed prior to a calibration or becomes exposed other than in a known way with a predetermined doεe of light, the inεtrument can be programmed to diεcontinue the calibration and verification procedure, εuch as by rejecting the color standard. According to yet another embodiment of this, invention, FIGS. 11 and 12 show calibration and verification apparatus 1000. FIG. 11 iε an exploded perεpective view of apparatus 1000 and FIG. 12 is an assembled perspective view of apparatuε 1000. Apparatuε 1000 includeε release liner 1010, sanitary layer 1020, color standard 1030, and photoεensitive layer 1040. A cap (not shown in FIGS. 11 and 12) can alεo be uεed according to thiε embodiment of the invention, but is optional. Also, while release liner 1010 and εanitary layer 1020 are preferred componentε of apparatuε 1000, they are alεo optional according to thiε invention. Release liner 1010 has first εurface 1012, which faceε downward in FIG. 11, and εecond εurface 1014, which faceε upward in FIG. 11. Preferably, firεt surface 1012 of release liner 1010 attaches to distal surface 1062 of color meaεuring inεtrument head 1060, which includeε round window 1063 through which color meaεurementε are made. Like release liner 910, 1010 is preferably subεtantially optically opaque, to prevent photosenεitive surface of layer 1040 from being exposed to electromagnetic radiation before calibrating a color measuring instrument with apparatus 1000. Sanitary layer 1020 has first surface 1022, which faceε downward in FIG. 11, and εecond surface 1024, which faces upward in FIG. 10. Sanitary layer 1020 has optically tranεparent aperture 1026, εuch aε a hole or transparent film, for exposing color standard 1030 and photoεensitive layer 1040 when uεed as described below. Second surface 1014 of release liner 910 can be attached to firεt εurface 1022 of εanitary layer 1020 with an adheεive, or any other conventional meanε. It will be appreciated that while releaεe liner 1010 and εanitary layer 1020 are attached, they can be separated if and when desired. For example, when liner 1010 and layer 1020 are attached to each other by an adhesive, they can be separated without destroying εanitary layer 1020 by εimply pulling tab 1018 of releaεe liner 1010. Color εtandard 1030 has first εurface 1032, which faceε downward in FIG. 11, and εecond εurface 1034, which faceε upward in FIG. 11. Standard 1030 iε mounted εo that its firεt εurface 1032 faceε second surface 1024 of εanitary layer 1020. Furthermore, standard 1030 is mounted so that region 1036 of first εurface 1032 is adjacent aperture 1026. In this way, region 1036 can be expoεed to light though aperture 1026 during operation. Like firεt surface 932 of color standard 930, the color of first surface 1032 of color standard 1030 εhould at least have a first color dispoεed thereon which is characterized by a firεt predetermined coloration having premeaεured color meaεurement value (ε) . Photosensitive layer 1040 has first surface 1042, which faces downward in FIG. 11, and second surface 1044, which faceε upward in FIG. 11. Layer 1040 iε preferably mounted εo that first surface 1042, which includes a photosensitive region, faces εecond surfaces 1024 and 1034. At least a part of photosensitive region 1046 must be expoεed during the expoεing εtep. In thiε embodiment, the part of photoεenεitive region 1046 that iε exposed is annular. As already diεcussed above with respect to apparatuε 900, photoεensitive portion 1046 of layer 1040 changes color in a known way when exposed to a predetermined dose of visible light. Layer 1040 can have tab portion 1048 for a user to grasp when removal is desired. Second surface 1024 of sanitary layer 1020. can be removably attached to at leaεt one of firεt surfaces 1032 and 1042. When a sanitary layer is not used in accordance with thiε invention, the technician calibrating the inεtrument can εterilize the skin, and/or the color measuring inεtrument head, with a εterilizing agent (e.g., alcohol). The sizes of various componentε uεed in accordance with thiε invention are now deεcribed. The area within aperture 1026 may be larger than the area within window 1063 εo that inner rim 1029 of layer 1020 doeε not interfere with color measurements. Also, to enεure that at leaεt a portion of photoεenεitive region 1046 iε expoεed during color measurements, the εurface area of region 1036 may be εmaller than the area within aperture 1026. And finally, to enεure accurate calibration and verification, the εurface area of region 1036 may be larger than the εurface area of region 1046. According to a further embodiment of this invention, FIGS. 13-15 εhow calibration and verification apparatus 1100. As shown best in FIGS. 13 and 14, apparatus 1100 can include photosenεitive layer 1110, color standard 1120, and release liner 1130. Photosensitive layer 1110 has firεt εurface 1112, second surface 1114, and an optically transparent aperture 1116. First surface 1112 has at least a first region that is photosenεitive. Second εurface 1114 is preferably attached to annular portion 1128 of firεt εurface 1122 with any conventional adheεive. Region 1117 of firεt εurface 1112 preferably changeε color in a known way when expoεed to a predetermined doεe of light. In particular, that region preferably changeε color in a known amount (εuch aε by darkening or lightening it) when region 1117 iε expoεed to a predetermined dose of visible light. Aε εhown in FIG. 15, region 1117 can be annular. Color εtandard 1120 haε first surface 1122 and εecond εurface 1124. Firεt εurface 1122 is mounted so that it faceε εecond εurface 1114 of layer 1110 and εo that firεt portion 1126 of εtandard 1120 iε adjacent optically tranεparent aperture 1116. Firεt surface 1112 can have one or more different colors characterized by predetermined coloration having premeasured color measurement value (s) . A εanitary layer (not εhown) can alεo be included to prevent tranεmission of germε and εuch between patientε aε explained above and εhown in FIGS. 9-12, for example. Second εurface 1134 of release liner 1130 is preferably releasably mounted εo that it faces first surface 1112 in εuch a way that it preventε light from becoming incident on annular region 1117 of photosensitive layer 1110 when liner 1130 is attached. To enεure accurate calibration and verification, the εurface area of region 1117 is preferably smaller than region 1126 and region 1126 iε preferably centrally located. Therefore, releaεe liner 1130 iε preferably substantially opaque to visible light and forms a light tight εeal with photosensitive 1120, such aε with a releasable adhesive. Also, releaεe liner 1130 can also include tab 1136 so that a user can easily remove liner 1130 from photosenεitive layer 1110 and color standard 1120 before calibration or verification. Apparatus 1100 can further include a cap (not εhown) . According to a another embodiment of thiε invention, FIGS. 16-18 εhow calibration and verification apparatuε 1200. Aε εhown best in FIGS. 16 and 17, apparatuε 1200 can include color standard 1210 and release liner 1230. Apparatuε 1200 is essentially the same as apparatus 1100, except that apparatus 1100 includes a color standard with an integrated photosenεitive portion. Color standard 1210 haε εurface 1211 with at leaεt first region 1212 and second region 1214. Firεt region 1212 has at least a first color characterized by a firεt predetermined coloration having premeaεured color meaεurement value (ε) . Firεt region 1212 of surface 1211 can have two or more different colors, including a εecond color characterized by a second predetermined coloration having premeasured color measurement value (s). Second region 1214 is photosenεitive. To enεure accurate calibration and verification, the εurface area of region 1214 iε preferably εmaller than region 1212 and region 1212 is preferably centrally located. A sanitary layer (not shown) can also be included to prevent tranεmiεεion of germε and εuch between patientε aε explained above and εhown in FIGS. 9-12, for example. Release liner 1230 is preferably releasably mounted so that it faces εurface 1211 of color εtandard 1210 in such a way that it prevents light from becoming incident on εecond portion 1214 when liner 1230 is mounted or attached to color standard 1210. Therefore, release liner 1230 is preferably substantially opaque to visible light and formε a light tight εeal with color εtandard 1210 on firεt portion 1214. Also, release liner 1230 can also include tab 1236 εo that a uεer can easily remove liner 1230 from color standard 1210 before calibration or verification. Apparatuε 1200 can include a cap (not εhown) for handling color εtandard 1210 during calibration and verification. According to a further embodiment of thiε invention, FIGS. 19-21 show calibration and verification apparatus 1300. As εhown beεt in FIGS. 19 and 20, apparatuε 1300 can include photosensitive layer 1310, color standard 1320, and release liner 1330. Photosenεitive layer 1310 haε firεt surface 1312, second surface 1314. Firεt εurface 1312 haε at leaεt firεt region 1315 that iε photoεenεitive. Color εtandard 1320 haε firεt εurface 1322 and εecond εurface 1324. Second εurface 1324 iε attached to first portion 1316 of layer 1310. In thiε way, firεt εurface 1322 is mounted εo that it faceε the εame direction aε firεt εurface 1312. Thiε arrangement allowε a εimultaneouε color meaεurement, if deεired. Firεt εurface 1322 can have one or more colorε characterized by predetermined colorationε having premeaεured color measurement value (s) . To enεure accurate calibration and verification, the εurface area of annular region 1315 iε preferably εmaller, and moεt preferably εubstantially εmaller, than region 1322 and region 1322 iε preferably centrally located. It will be appreciated that photoεenεitive region can be any εhape and therefore need not be annular. A sanitary layer (not shown) can also be releaεably attached to a portion of firεt εurface 1312 of color standard 1310 to prevent transmission of germs and such between patients as described above and shown in FIGS. 9-12, for example. As shown beεt in FIG. 19, εecond εurface 1334 of releaεe liner 1330 iε preferably releaεably mounted εo that it faceε firεt εurface 1312 of layer 1310 in such a way that it blocks light from becoming incident on region 1315 of photosenεitive layer 1310 when liner 1330 iε attached. Apparatuε 1300 can alεo include a cap (not εhown) . The use of a cap can help a user align apparatuε 1300 on the head of the color meaεuring inεtrument, and provide a εubεtantially opaque back εurface for the apparatuε . Thuε, it is apparent that there has been provided, in accordance with the invention, methodε and apparatus of color calibration and verification that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with εpecific embodi entε thereof, it iε evident that many alternativeε, modificationε and variationε will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it iε intended to embrace all εuch alternativeε, modifications and variations as fall within the spirit of the appended claimε.

Claims: CLAIMS The Invention Claimed Is 1. A method of calibrating a color measuring instrument with a color standard and verifying said color εtandard and said calibration, said method comprising: providing a color standard having a εurface with at least two different colors arranged for a simultaneouε color measurement; calibrating said inεtrument; and verifying that εaid color εtandard uεed in calibration iε an authorized color εtandard of said predetermined specification and that the calibration of the color measurement instrument haε achieved predetermined specified results. 2. The method of claim 1 wherein said providing compriseε : providing a color standard having a first of εaid colorε characterized by a first predetermined coloration having premeasured color measurement value (ε) and a εecond of εaid colors characterized by a second predetermined coloration having premeaεured color meaεurement value (ε) . 3. The method of claim 2 wherein said calibrating comprises: measuring at leaεt a first known and predetermined portion of said color standard surface to obtain preliminary calibration color measurement value (s) ; adjuεting the inεtrument output to correεpond to previouεly eεtabliεhed calibrationε, uεing εaid portion of εaid color standard; remeaεuring εaid portion of εaid color εtandard to obtain calibration color measurement value (ε) ,- and comparing said calibration color measurement value (s) with a calibration's premeasured color measurement value (ε) for the εame known and predetermined portion of εaid color εtandard εurface to ensure that said calibration color meaεurement value (ε) and said calibration's premeasured color measurement value (ε) iε εubεtantially the εame and therefore to ensure that calibration has achieved predetermined specified reεults. 4. The method of claim 3 wherein said verifying comprises : measuring at least a second known and predetermined portion of said color standard εurface to obtain verification color meaεurement value (ε), and determining that said verification color measurement value (s) iε εubεtantially equal to a verification' ε premeasured color measurement value (ε) for the εame known and predetermined portion of the said color standard εurface . 5. The method of claim 2 wherein εaid providing comprises providing a color standard wherein said at least two colors of predetermined coloration are dispoεed on said color standard εurface in a known ratio of surface areas . 6. The method of claim 2 wherein said providing compriεeε providing a color εtandard wherein εaid at least two colors of predetermined coloration are dispoεed on εaid color εtandard εurface in a known configuration of surface areaε . 7. The method of claim 6 wherein said providing compriεeε providing a color εtandard wherein said at least two colσrε of predetermined coloration are diεposed on said color εtandard εurface with a known radial diεpoεition. 8. The method of claim 7 wherein εaid providing compriεes providing a color standard wherein εaid firεt color of predetermined coloration iε on a central region that is centrally located on said εtandard εurface and wherein εaid εecond color of predetermined coloration iε diεpoεed on an outer region that iε radially outεide εaid central region. 9. The method of claim 8 wherein εaid providing comprises providing a color εtandard wherein εaid εecond color of predetermined coloration iε diεpoεed on an annular region of said standard εurface. 10. The method of claim 8 wherein εaid providing comprises providing a color standard wherein said centrally located region has a εurface area that iε larger than a εurface area of εaid annular region. 11. The method of claim 6 wherein εaid providing comprises providing a color standard wherein said firεt color of predetermined coloration iε diεposed on at least two noncontiguous regions on said color standard surface . 12. The method of claim 11 wherein said providing compriseε providing a color standard wherein said second color of predetermined coloration is diεposed on at least two additional noncontiguous regions on said color standard surface . 13. The method of claim 12 wherein εaid providing compriεeε providing a color standard wherein said colorε of predetermined coloration on said εtandard εurface have a mottled appearance. 14. The method of claim 6 wherein εaid providing compriεeε providing a color εtandard wherein εaid first color of predetermined coloration is diεpoεed on at leaεt two contiguous regions on said color standard εurface . 15. The method of claim 4 wherein εaid meaεuring a firεt known portion compriεeε masking said second known portion. 16. The method of claim 15 wherein said calibrating comprises measuring a first known portion wherein εaid firεt known portion iε a region on which εaid firεt color of predetermined coloration is dispoεed. 17. The method of claim 16 wherein εaid verifying compriεeε meaεuring a εecond known portion wherein said second known portion is a region on which said second color of predetermined coloration is disposed. 18. The method of claim 15 wherein said verifying comprises meaεuring a εecond known portion wherein said second known portion is a portion on which εaid first color of predetermined coloration and said εecond color of predetermined coloration are disposed. 19. The method of claim 15 wherein said verifying compriεeε meaεuring a εecond known portion consisting esεentially of a region on which εaid εecond color of predetermined coloration iε diεpoεed. 20. The method of claim 15 wherein εaid verifying compriεeε meaεuring a εecond known portion conεiεting eεsentially of a portion on which a predetermined combination of said first color of predetermined coloration and said second color of predetermined coloration is diεpoεed. 21. The method of claim 15 wherein εaid calibrating compriεeε meaεuring a first known portion wherein said first known portion iε a region on which εaid εecond color of predetermined coloration iε disposed. 22. The method of claim 21 wherein said verifying compriεeε measuring a εecond known portion wherein εaid εecond known portion iε a region on which εaid firεt color of predetermined coloration iε disposed. 23. The method of claim 21 wherein εaid verifying compriεeε measuring a second known portion wherein said second known portion is a portion on which said first color of predetermined coloration and said second color of predetermined coloration are dispoεed. 24. The method of claim 21 wherein εaid verifying compriεeε measuring a second known portion consisting essentially of a portion on which said first color of predetermined coloration is diεpoεed. 25. The method of claim 21 wherein εaid verifying compriεeε meaεuring a εecond known portion, conεiεting eεεentially of a portion on which a predetermined combination of εaid firεt color of predetermined coloration and said second color of predetermined coloration is disposed. 26. The method of claim 15 wherein said calibrating comprises measuring a firεt known portion wherein εaid firεt known portion iε a portion on which said firεt color of predetermined coloration and εaid second color of predetermined coloration are dispoεed. 27. The method of claim 15 wherein said calibrating comprises measuring a first known portion, wherein said first known portion iε εelected from a group consisting esεentially of a portion on which said firεt color of predetermined coloration iε diεpoεed, a portion on which εaid εecond color of predetermined coloration iε diεposed, and a portion on which a predetermined combination of said firεt color of predetermined coloration and εaid εecond color of predetermined coloration iε diεpoεed. 28. The method of claim 27 wherein εaid calibrating compriεes measuring a first known portion conεisting essentially of a portion on which said firεt color of predetermined coloration iε diεpoεed. 29. The method of claim 27 wherein εaid calibrating comprises measuring a firεt known portion consisting essentially of a portion on which said εecond color of predetermined coloration is disposed. 30. The method of claim 27 wherein said calibrating compriεes measuring a first known portion conεiεting eεεentially of a portion on which εaid predetermined combination iε disposed. 31. The method of claim 15 wherein said maεk haε an aperture, εaid meaεuring a firεt known portion compriεeε poεitioning εaid maεk adjacent εaid color εtandard εurface εo that εaid firεt known portion is meaεurable and said second known portion iε not meaεurable . 32. The method of claim 31 wherein εaid first known portion is one of a plurality of calibration portionε diεpoεed on εaid color εtandard εurface and εaid maεk has a plurality of operable positionε that correspond to said calibration portionε, and wherein εaid poεitioning compriεeε poεitioning said maεk in one of said plurality of operable poεitionε to εelect one of εaid calibration portionε. 33. The method of claim 4 wherein εaid measuring a second known portion compriseε masking εaid firεt known portion. 34. The method of claim 33 wherein said verifying comprises measuring a second known portion wherein said second known portion is a region on which said first color of predetermined coloration is disposed. 35. The method of claim 33 wherein said verifying comprises measuring a second known portion wherein said second known portion is a region on which said second color of predetermined coloration is disposed. 36. The method of claim 33 wherein said verifying compriseε meaεuring a εecond known portion wherein said second known portion is a portion on which εaid first color of predetermined coloration and said second color of predetermined coloration are diεpoεed. 37. The method of claim 33 wherein εaid verifying comprises measuring a εecond known portion, wherein εaid εecond known portion iε εelected from a group conεiεting essentially of a portion on which said firεt color of predetermined coloration iε diεpoεed, a portion on which said second color of predetermined coloration is disposed, and a portion on which a predetermined combination of said firεt color of predetermined coloration and εaid second color of predetermined coloration is dispoεed. 38. The method of claim 37 wherein said verifying compriseε measuring a second known portion consiεting eεεentially of a portion on which εaid firεt color of predetermined coloration iε disposed. 39. The method of claim 37 wherein said verifying comprises measuring a second known portion consisting essentially of a portion on which said second color of predetermined coloration is diεposed. 40. The method of claim 37 wherein said verifying compriseε meaεuring a εecond known portion conεisting esεentially of a portion on which εaid predetermined combination iε disposed. 41. The method of claim 36 wherein εaid maεk has an aperture, said meaεuring a εecond known portion compriεeε poεitioning εaid maεk adjacent εaid color εtandard surface so that εaid second known portion is measurable and said firεt known portion is not measurable . 42. The method of claim 41 wherein εaid εecond known portion iε one of a plurality of calibration portionε diεpoεed on said color standard εurface and said mask haε a plurality of operable poεitionε that correspond to said calibration portionε, and wherein said positioning compriseε poεitioning said mask in one of said operable positionε to εelect one of εaid calibration portionε. 43. The method of claim 4 wherein εaid firεt known portion and εaid second known portion are the same . 44. The method of claim 43 wherein εaid determining that εaid verification color meaεurement value (ε) iε εubεtantially equal compriεeε: calculating computed color meaεurement value (ε) baεed on εaid verification color meaεurement value (ε) ; and determining that εaid computed color meaεurement value (ε) are εubstantially equal to said verification's premeasured color meaεurement value (ε). 45. The method of claim 44 wherein εaid firεt known portion iε εelected from a group conεisting eεεentially of a portion on which εaid firεt color iε diεpoεed, a portion on which εaid second color is dispoεed, and a portion on which a predetermined combination of said first color of predetermined coloration and said second color of predetermined coloration is diεposed. 46. The method of claim 45 wherein said calculating computed color measurement value (s) compriεeε adding predetermined differential color meaεurement value (ε) to εaid verification color meaεurement value (ε) to obtain said computed color meaεurement value (ε) . 47. The method of claim 46 wherein εaid firεt known portion conεiεtε eεεentially of a region on which εaid first color of predetermined coloration is diεpoεed, and wherein εaid predetermined differential color meaεurement value (s) iε at leaεt partially baεed on εaid εecond predetermined coloration' ε premeasured color measurement value (ε) . 48. The method of claim 46 wherein εaid firεt known portion consists essentially of a region on which said second color is diεpoεed, and wherein said predetermined differential color measurement value (s) is at least partially based on εaid firεt predetermined coloration' ε premeaεured color meaεurement value (s) . 49. The method of claim 45 wherein εaid determining of εaid calculated color meaεurement value (ε) compriεes subtracting said predetermined differential color measurement value (ε) from said verification color measurement value (ε) to obtain εaid computed color meaεurement value (ε) . 50. The method of claim 49 wherein εaid firεt known portion conεiεtε eεεentially of a portion on which εaid predetermined combination of εaid firεt color of predetermined coloration and εaid εecond color of predetermined coloration iε diεpoεed, and wherein εaid predetermined differential color meaεurement value (s) is at leaεt partially baεed on said first predetermined coloration's premeaεured color meaεurement value (ε) . - 51. The method of claim 49 wherein εaid firεt known portion conεists esεentially of a portion on which εaid predetermined combination of εaid firεt color of predetermined coloration and said second color of predetermined coloration is dispoεed, and wherein said predetermined differential color measurement value (s) are at leaεt partially baεed on said second predetermined coloration's premeasured color measurement value (s) . 52. The method of claim 4 wherein εaid providing a color εtandard compriεeε providing a color εtandard having at leaεt two different colorε, a firεt of εaid colors being disposed on a first surface of said color standard and being characterized by a firεt predetermined coloration having premeaεured color meaεurement value (ε) and a εecond of εaid colors being disposed on a second surface of said color standard and being characterized by a εecond predetermined coloration having premeasured color measurement value (ε) . 53. The method of claim 52 wherein εaid meaεuring a first known portion compriseε measuring at least said firεt known and predetermined portion of εaid firεt εurface of εaid color εtandard to obtain εaid calibration color measurement value (s) . 54. The method of claim 52 wherein said meaεuring a second known portion compriseε measuring at leaεt εaid second known and predetermined portion of εaid εecond εurface of εaid color εtandard to obtain εaid verification color measurement value (s) . 55. The method of claim 52 wherein εaid color εtandard firεt εurface and εaid color εtandard . εecond εurface are εeparable . 56. The method of claim 52 wherein εaid color εtandard firεt surface and said color standard second surface are inseparable. 57. The method of claim 56 wherein εaid inεeparable firεt and εecond εurfaceε are diεpoεed on oppoεite εideε of a flat εubεtrate. 58. The method of claim 1 wherein said color measuring instrument has a head with a window, εaid providing a color standard compriseε providing a color εtandard having at leaεt two different colors arranged for a simultaneous color measurement within εaid window. 59. The method of claim 58 wherein εaid window haε a εubεtantially round εhape, εaid providing a color standard compriseε providing a color εtandard having at leaεt two different colorε arranged for a εimultaneous color measurement within said subεtantially round window. 60. The method of claim 1 wherein said at least two different colors includes a first color having a firεt εurface area and a εecond color having a εecond εurface area, εaid providing comprises providing a color standard wherein said first surface area is εubstantially larger than said εecond surface area. 61. The method of claim 1 wherein said providing compriseε : providing a color standard having a first color that is characterized by a first predetermined coloration having premeasured color meaεurement value (ε) and a εecond color that iε photoεenεitive . 62. The method of claim 61 wherein εaid calibrating compriεeε meaεuring a known and predetermined portion of εaid color standard to obtain calibration color measurement value (s), and wherein εaid verifying compriεeε meaεuring said portion to obtain verification color measurement value (ε), εaid method further compriεing: expoεing at leaεt εaid εecond color to a predetermined doεe of light after εaid calibrating εuch that εaid calibration color meaεurement value (s) and εaid verification color meaεurement value (ε) are different . 63. The method of claim 61 wherein εaid firεt color haε a first surface area and εaid εecond color haε a εecond εurface area, εaid providing comprises providing a color standard wherein said first εurface area is larger than said second surface area. 64. The method of claim 63 wherein said providing compriseε providing a color εtandard wherein εaid firεt εurface area iε εubεtantially larger than εaid εecond εurface area. 65. The method of claim 61 wherein εaid calibrating comprises measuring a known and predetermined portion of said color standard to obtain calibration color measurement value (ε), and wherein said verifying compriseε meaεuring said portion to obtain verification color meaεurement value (s) , said method further comprising: expoεing at leaεt εaid second color to a predetermined dose of light after εaid calibrating εuch that εaid calibration color meaεurement value (ε) and εaid verification color meaεurement value (ε) are different . 66. The method of claim 65 wherein said providing comprises providing a color standard that iε εubstantially opaque to said light. 67. The method of claim 1 wherein εaid providing comprises providing a color standard that iε substantially opaque to light. 68. The method of claim 1 wherein said color meaεuring inεtrument has a head with a window, and wherein said providing a color standard compriεeε providing a color εtandard having at least two different colors arranged for a εimultaneouε color meaεurement within εaid window. 69. A color measuring instrument that can be calibrated and verified uεing a color εtandard having a εurface with at leaεt two different colors arranged for a simultaneous color measurement, εaid inεtrument comprising: meanε for calibrating with εaid color standard; and means for verifying that said color εtandard used in calibration is an authorized color standard of said predetermined εpecification and that the calibration of the color measurement inεtrument haε achieved predetermined εpecified reεults. 70. The inεtrument of claim 69 wherein a firεt of εaid colorε iε characterized by a firεt predetermined coloration having premeaεured color meaεurement value (ε) and a εecond of εaid colors is characterized by a second predetermined coloration having premeasured color measurement value (ε) . 71. The inεtrument of claim 70 wherein said means for calibrating compriεeε: meanε for measuring at least a first known portion of εaid color εtandard εurface to obtain preliminary calibration color measurement value (s) ; meanε for adjuεting the instrument output to correspond to previously established calibrations using said portion of εaid color standard; means for remeasuring the εaid portion of εaid color εtandard to obtain calibration color measurement value (s); and means for comparing said calibration color meaεurement value (ε) with a calibration' ε premeasured color meaεurement value (s) for the same known and predetermined portion of said color standard surface to ensure that said calibration color measurement value (s) and said calibration's premeasured color measurement value (s) is substantially the same and therefore to ensure that calibration has achieved predetermined specified results . 72. The instrument of claim 71 wherein said means for verifying comprises: meanε for meaεuring at leaεt a εecond known and predetermined portion of εaid color εtandard εurface to obtain verification color meaεurement value (s) ; and meanε for determining that εaid verification color meaεurement value (ε) iε εubstantially equal to a verification's premeasured color measurement value (ε) for the εame known and predetermined portion of the εaid color εtandard εurface . 73. The inεtrument of claim 71 wherein said means for meaεuring a firεt known portion can measure a region on which said first color of predetermined coloration iε diεpoεed. 74. The inεtrument of claim 72 wherein εaid meanε for meaεuring a εecond known portion can measure a region on which εaid εecond color of predetermined coloration iε diεpoεed. 75. The inεtrument of claim 72 wherein said means for measuring a second known portion can measure a portion on which said first color of predetermined coloration and εaid second color of predetermined coloration are disposed. 76. The instrument of claim 72 wherein εaid means for measuring a second known portion can measure a region consiεting essentially of said second color of predetermined coloration. 77. The instrument of claim 72 wherein said means for measuring a second known portion can measure a portion consisting esεentially of a predetermined combination of said firεt color of predetermined coloration and said second color of predetermined coloration is disposed. 78. The instrument of claim 72 wherein said means for meaεuring a first known portion can measure a region on which said second color of predetermined coloration is disposed. 79. The instrument of claim 78 wherein said means for measuring a second known portion can measure a region on which said first color of predetermined coloration is dispoεed. 80. The inεtrument of claim 78 wherein εaid meanε for meaεuring a εecond known portion can meaεure a portion on which εaid firεt color of predetermined coloration and εaid εecond color of predetermined coloration are diεpoεed. 81. The inεtrument of claim 78 wherein εaid meanε for meaεuring a second known portion can measure a portion consiεting eεsentially of said first color of predetermined coloration. 82. The instrument of claim 78 wherein said means for measuring a second known portion can meaεure a portion conεiεting essentially of a predetermined combination of said first color of predetermined coloration and said second color of predetermined coloration. 83. The instrument of claim 78 wherein εaid means for measuring a first known portion can measure a portion on which εaid firεt color of predetermined coloration and εaid εecond color of predetermined coloration are diεposed. 84. The instrument of claim 78 wherein said means for meaεuring a first known portion can measure, a portion εelected from a group conεiεting eεεentially of a portion on which εaid firεt color of predetermined coloration is dispoεed, a portion on which εaid second color of predetermined coloration is disposed, and a portion on which a predetermined combination of said firεt color of predetermined coloration and εaid εecond color of predetermined coloration iε disposed. 85. The instrument of claim 84 wherein said means for meaεuring a firεt known portion can meaεure a portion consisting esεentially of εaid firεt color of predetermined coloration. 86. The inεtrument of claim 84 wherein εaid meanε for meaεuring a firεt known portion can meaεure a portion conεiεting eεεentially of εaid εecond color of predetermined coloration. 87. The instrument of claim 84 wherein said meanε for measuring a first known portion can measure a portion conεiεting essentially of said predetermined coloration combination. 88. The inεtrument of claim 84 wherein εaid means for measuring at least a first known portion comprises a mask for masking εaid εecond known portion. 89. The instrument of claim 88 wherein said mask has an aperture, said meanε for meaεuring a firεt known portion comprises means for positioning εaid maεk adjacent εaid color of predetermined coloration standard surface εo that εaid first known portion is meaεured and εaid εecond known portion iε meaεured. 90. The inεtrument of claim 89 wherein εaid firεt known portion iε one of a plurality of calibration portionε diεposed on said color standard surface and said mask haε a plurality of operable poεitionε that correεpond to said calibration portions, and wherein εaid meanε for poεitioning can position said maεk in one of εaid plurality of operable poεitionε to εelect one of said calibration portions. 91. The inεtrument of claim 72 wherein εaid meanε for meaεuring a εecond known portion can meaεure a region on which εaid firεt color of predetermined coloration iε diεpoεed. 92. The inεtrument of claim 91 wherein εaid means for measuring a second known portion can meaεure a region on which said second color of predetermined coloration is disposed. 93. The instrument of claim 91 wherein εaid meanε for meaεuring a εecond known portion can meaεure a portion on which εaid firεt color of predetermined coloration and εaid εecond color of predetermined coloration are disposed. 94. The instrument of claim 72 wherein εaid means for measuring a second known portion can measure a portion selected from a group consisting of a portion consisting esεentially of εaid first color of predetermined coloration, a portion consiεting eεεentially of said second color of predetermined coloration, and a portion conεiεting esεentially of a predetermined combination of εaid firεt color and said εecond color. 95. The instrument of claim 94 wherein said means for meaεuring a second known portion can measure a portion consiεting eεεentially of εaid first color of predetermined coloration. 96. The instrument of claim 94 wherein εaid meanε for meaεuring a εecond known portion consiεting eεεentially of a portion on which εaid εecond color of predetermined coloration iε diεpoεed. 97. The inεtrument of claim 94 wherein said means for measuring a second known portion consiεting eεεentially of εaid predetermined coloration combination. 98. The inεtrument of claim 94 wherein εaid means for measuring a second known portion compriεeε a maεk for masking said firεt known portion. 99. The instrument of claim 98 wherein said mask haε an aperture, said means for measuring a second known portion compriseε means for positioning εaid mask adjacent said color standard surface εo that εaid second known portion is meaεurable and εaid firεt known portion iε not meaεurable. 100. The instrument of claim 99 wherein said second known portion is one of a plurality of calibration portions disposed on said color standard surface and said mask haε a plurality of operable poεitionε that correεpond to said calibration portions, and wherein said meanε for poεitioning can position said maεk in one of εaid operable poεitions to select one of said calibration portionε. 101. The inεtrument of claim 72 wherein said means for measuring a first known portion and said meanε for measuring a εecond known portion are the εame. 102. The instrument of claim 101 wherein said meanε for determining that said verification color meaεurement value (s) is εubstantially equal to εaid verification' ε premeaεured color meaεurement value (ε) comprises : means for calculating computed color measurement value (s) baεed on the verification color meaεurement value (s); and means for determining that the computed color measurement value (s) are εubεtantially equal to the verification' ε premeaεured color meaεurement value (ε) . 103. The inεtrument of claim 102 wherein said first known portion iε selected from a group consiεting a portion consisting essentially of said first color of predetermined coloration, a portion conεisting essentially of said εecond color of predetermined coloration, and a portion conεisting esεentially of a predetermined combination of said first color and said second color. 104. The instrument of claim 103 wherein said means for determining said computed color measurement value (s) comprises means for adding predetermined differential color measurement value (s) to said verification color meaεurement value (s) to obtain εaid computed color meaεurement value (s) . 105. The instrument of claim 104 wherein said predetermined differential color meaεurement value (s). is at least partially based on said first predetermined coloration's premeasured color measurement value (s), εaid εecond predetermined coloration' s premeasured color measurement value (s), or a combination thereof. 106. The instrument of claim 103 wherein said means for determining said computed color measurement value (s) compriseε means for subtracting said predetermined differential color measurement value (s) from εaid verification color meaεurement value (ε) to obtain εaid computed color meaεurement value (s) . 107. The instrument of claim 106 wherein said predetermined differential color measurement value (s) is at leaεt partially baεed on said first predetermined coloration' s premeasured color meaεurement value (s) . 108. The instrument of claim 69 wherein εaid color εtandard has a first color that iε characterized by a first predetermined coloration having premeaεured color meaεurement value (s) and a second color that iε photosensitive . 109. The instrument of claim 108 wherein εaid meanε for calibrating comprises means for measuring a known and predetermined portion of εaid color standard to obtain calibration color measurement value (s), and wherein said means for verifying comprises means for meaεuring εaid portion to obtain verification color meaεurement value (s), said instrument further comprising: means for exposing at least said second color to a predetermined doεe of light εuch that said calibration color measurement value (s) and said verification color measurement value (s) are different. 110. The instrument of claim 69 wherein said wherein said color standard iε εubεtantially opaque to light and wherein εaid meanε for calibrating and εaid means for verifying is for calibrating and verifying with εaid color εtandard. 111. The inεtrument of claim 69 wherein εaid meanε for calibrating compriεes means for meaεuring a known and predetermined portion of εaid color εtandard to obtain calibration color meaεurement value (s), and wherein said means for verifying compriεeε meaεuring εaid portion to obtain verification color meaεurement value (ε), said instrument further compriεing: meanε for expoεing at least said second color to a predetermined doεe of light εuch that εaid calibration color meaεurement value (ε) and εaid verification color meaεurement value (ε) are different. 112. The inεtrument of claim 69 wherein εaid color meaεuring instrument has a head with a window, and wherein said color standard compriseε at leaεt two different colorε arranged for a εimultaneouε color measurement within said window. 113. A method of calibrating a color measuring instrument with a color standard and verifying said color standard and said calibration, said method compriεing: providing a color standard having a surface with at leaεt a firεt region and a εecond region, wherein said first region haε a first color characterized by a first predetermined coloration having premeasured color meaεurement value (s), and wherein said εecond region iε photoεenεitive; calibrating εaid inεtrument with εaid color εtandard; expoεing at leaεt εaid εecond region with light; and verifying that εaid color standard used in calibration is an authorized color standard of εaid predetermined specification and that the calibration of the color measurement inεtrument haε achieved predetermined εpecified reεultε. 114. The method of claim 113 wherein εaid providing compriεeε : providing a color εtandard having a firεt of εaid colorε characterized by a firεt predetermined coloration having premeaεured color meaεurement value (ε) and a εecond of εaid colorε characterized by a εecond predetermined coloration having premeaεured color meaεurement value (ε) . 115. The method of claim 114 wherein said calibrating compriseε: measuring at least a firεt known and predetermined portion of εaid color εtandard εurface to obtain preliminary calibration color meaεurement value (s) ; adjuεting the instrument output to correspond to previouεly eεtabliεhed calibrationε, uεing said portion of εaid color standard; remeaεuring εaid portion of εaid color εtandard to obtain calibration color meaεurement value (s) ,- and comparing said calibration color meaεurement value (ε) with a calibration' ε premeaεured color measurement value (s) for the same known and predetermined portion of εaid color εtandard εurface to enεure that εaid calibration color meaεurement value (ε) and εaid calibration's premeasured color measurement value (s) iε εubεtantially the same and therefore to ensure that calibration haε achieved predetermined εpecified reεultε. 116. The method of claim 115 wherein εaid verifying comprises: measuring at least a εecond known and predetermined portion of εaid color εtandard εurface to obtain verification color meaεurement value (ε), and determining that εaid verification color meaεurement value (ε) iε εubεtantially equal to a verification' ε premeaεured color meaεurement value(ε) for the same known and predetermined portion of the said color εtandard surface. 117. The method of claim 113 wherein said calibrating comprises at least meaεuring a known and predetermined portion of εaid color εtandard to obtain calibration color meaεurement value (s), wherein said verifying comprises at least measuring said portion to obtain verification color measurement value (ε), and wherein said exposing comprises exposing at least said second region to a predetermined dose of light after said calibrating such that εaid calibration color meaεurement value (ε) and said verification color measurement value (s) are different. 118. The method of claim 113 wherein at leaεt one of εaid calibrating and verifying compriεeε meaεuring the color of εaid portion, wherein εaid portion compriεeε εaid firεt region and εaid εecond region, wherein εaid firεt region has a firεt εurface area and εaid εecond region haε a second surface area, εaid firεt εurface area being larger than εaid εecond εurface area. 119. The method of claim 113 wherein εaid providing compriεes providing a color standard having a εurface with at least two different colors arranged for a εimultaneouε color meaεurement. 120. The method of claim 113 wherein εaid color meaεuring inεtrument has a head with a window, said providing a color εtandard compriεeε providing a color εtandard having at leaεt two different colors arranged for a simultaneouε color measurement within said window. 121. The method of claim 120 wherein said window has a εubεtantially round εhape, εaid providing a color εtandard compriεeε providing a color standard having at least two different colors arranged for a simultaneouε color meaεurement within said substantially round window. 122. The method of claim 113 wherein εaid providing compriεeε providing a color εtandard that iε substantially opaque to light. 123. A color measuring instrument that iε calibrated and verified uεing a color εtandard having a εurface with at leaεt two different colorε with at least a firεt region and a εecond region, wherein εaid first region has a firεt color characterized by a firεt predetermined coloration having premeasured color measurement value (s), and wherein εaid second region is photosenεitive, εaid inεtrument compriεing: meanε for calibrating with εaid color εtandard; meanε for expoεing at leaεt εaid εecond region with light; and meanε for verifying that εaid color εtandard uεed in calibration iε an authorized color εtandard of εaid predetermined εpecification and that the calibration of the color meaεurement inεtrument haε achieved predetermined εpecified reεultε. 124. The inεtrument of claim 123 wherein a firεt of εaid colorε iε characterized by a firεt predetermined coloration having premeaεured color measurement value (s) and a εecond of εaid colorε iε characterized by a εecond predetermined coloration having premeaεured color measurement value (s) . 125. The inεtrument of claim 124 wherein εaid meanε for calibrating compriεes: means for measuring at least a first known portion of said color standard surface to obtain preliminary calibration color meaεurement value (s) ; meanε for adjuεting the inεtrument output to correεpond to previouεly eεtabliεhed calibrationε uεing εaid portion of εaid color standard; means for remeasuring the εaid portion of εaid color εtandard to obtain calibration color meaεurement value (ε) ; and meanε for comparing εaid calibration color meaεurement value (ε) with a calibration' ε premeaεured color measurement value (ε) for the εame known and predetermined portion of εaid color εtandard εurface to enεure that said calibration color meaεurement value (ε) and εaid calibration's premeasured color meaεurement value (ε) iε εubstantially the same and therefore to enεure that calibration haε achieved predetermined εpecified results . 126. The instrument of claim 125 wherein εaid meanε for verifying compriεeε : meanε for meaεuring at leaεt a εecond known and predetermined portion of εaid color εtandard surface to obtain verification color measurement value (s) ; and means for determining that said verification color measurement value (s) iε substantially equal to a verification's premeaεured color meaεurement value (ε) for the same known and predetermined portion of the εaid color εtandard surface. 127. The instrument of claim 126 wherein said means for measuring a first known portion can measure a region on which said first color of predetermined coloration is dispoεed. 128. The instrument of claim 126 wherein said means for measuring a second known portion can meaεure a region on which εaid εecond color of predetermined coloration iε diεpoεed. 129. A εyεtem for meaεuring the color of a εample εurface having an unknown coloration, εaid εyεtem compriεing: a color εtandard having a εurface with at leaεt two different colorε arranged for a simultaneous color meaεurement; and a color meaεuring inεtrument that can be calibrated and verified with said color εtandard. 130. A εyεtem for meaεuring the color of a sample surface having an unknown coloration, said εystem comprising: a color εtandard having a εurface with at leaεt two different colorε, a firεt of said colors being characterized by a firεt predetermined coloration having premeaεured color measurement value (s) and a εecond of εaid colorε that iε photoεensitive; and a color measuring instrument that can be calibrated and verified with said color standard. 131. A method of calibrating a color measuring inεtrument with a color standard and verifying said color standard and said calibration, said method comprising: providing a color standard having a surface with at least two different colorε arranged for a εimultaneouε color meaεurement, a firεt of εaid colorε being characterized by a firεt predetermined coloration having premeasured color measurement value (s) and a second of said colorε being characterized by a εecond predetermined coloration having premeaεured color measurement value (ε); calibrating εaid inεtrument, εaid calibrating compriεing: meaεuring at leaεt a firεt known and predetermined portion of εaid color εtandard εurface to obtain preliminary calibration color meaεurement value (s), adjusting the instrument output to correspond to previouεly eεtabliεhed calibrationε,. uεing εaid portion of εaid color εtandard and remeaεuring εaid portion of εaid color εtandard to obtain calibration color measurement value (s) and comparing said calibration color measurement value (ε) with a calibration' ε premeaεured color measurement value (s) for the same known and predetermined portion of said color εtandard εurface to enεure that εaid calibration color meaεurement value (ε) and said calibration's premeaεured color meaεurement value (s) is subεtantially the εame and therefore to ensure that calibration has achieved predetermined specified reεultε; and verifying that εaid color εtandard uεed in calibration iε an authorized color εtandard of εaid predetermined εpecification and that the calibration of the color meaεurement inεtrument has achieved predetermined specified reεultε, εaid verifying compriεing: measuring at least a second known and predetermined portion of εaid color standard surface to obtain verification color measurement value (s) , and determining that εaid verification color meaεurement value (ε) is subεtantially equal to a verification' ε premeaεured color meaεurement value (s) for the same known and predetermined portion of the said color standard surface. 132. The method of claim 131 wherein said providing comprises providing a color standard wherein εaid at leaεt two colorε of predetermined coloration are disposed on said color εtandard εurface in a known ratio of εurface areas . 133. The method of claim 131 wherein said providing compriseε providing a color εtandard wherein said at leaεt two colorε of predetermined coloration are diεpoεed on εaid color εtandard surface in a known configuration of surface areas. 134. The method of claim 133 wherein said providing compriεeε providing a color εtandard wherein εaid at leaεt two colorε of predetermined coloration are disposed on εaid color εtandard εurface with a known radial diεpoεition. 135. The method of claim 134 wherein εaid providing compriεeε providing a color standard wherein said first color of predetermined coloration is on a central portion that is centrally located on said εtandard εurface and wherein εaid εecond color of predetermined coloration iε diεpoεed on an outer portion that iε radially outεide εaid central portion. 136. The method of claim 135 wherein εaid providing compriεeε providing a color εtandard wherein said second color of predetermined coloration iε diεposed on an annular portion of said εtandard εurface. 137. The method of claim 135 wherein said providing compriseε providing a color standard wherein said centrally located portion has a surface area that is larger than a surface area of said annular portion. 138. The method of claim 133 wherein said providing comprises providing a color standard wherein εaid firεt color of predetermined coloration iε diεposed on at least two noncontiguouε portionε on εaid color εtandard surface. 139. The method of claim 138 wherein εaid providing compriεeε providing a color εtandard wherein εaid εecond color of predetermined coloration iε diεpoεed on at leaεt two additional noncontiguouε portions on said color standard εurface. 140. The method of claim 139 wherein εaid providing compriεeε providing a color εtandard wherein εaid colorε of predetermined coloration on εaid εtandard εurface have a mottled appearance. 141. The method of claim 131 wherein εaid measuring a first known portion compriεeε maεking εaid εecond known portion. 142. The method of claim 141 wherein said calibrating compriseε meaεuring a firεt known portion wherein εaid firεt known portion iε a region on which εaid firεt color of predetermined coloration iε disposed. 143. The method of claim 142 wherein said verifying comprises measuring a second known portion wherein said εecond known portion iε a region on which εaid second color of predetermined coloration is disposed. 144. The method of claim 142 wherein said verifying compriseε measuring a second known portion wherein εaid εecond known portion iε a region on which εaid first color of predetermined coloration and said second color of predetermined coloration are disposed. 145. The method of claim 142 wherein said verifying compriseε measuring a second known portion consiεting eεεentially of a region on which εaid εecond color of predetermined coloration iε diεpoεed. 146. The method of claim 142 wherein said verifying compriseε meaεuring a εecond known portion conεiεting eεεentially of a region on which a predetermined combination of εaid firεt color of predetermined coloration and εaid εecond color of predetermined coloration iε disposed. 147. The method of claim 141 wherein said calibrating compriseε meaεuring a firεt known portion wherein εaid firεt known portion iε a region on which said second color of predetermined coloration is disposed. 148. The method of claim 147 wherein said verifying comprises measuring a second known portion wherein said second known portion is a region on which said first color of predetermined coloration is diεposed. 149. The method of claim 147 wherein εaid verifying comprises measuring a second known portion wherein said second known portion is a region on which said first color of predetermined coloration and said εecond color of predetermined coloration are diεpoεed. 150. The method of claim 147 wherein said verifying compriseε meaεuring a εecond known portion conεiεting essentially of a region on which said first color of predetermined coloration is disposed. 151. The method of claim 147 wherein said verifying compriseε meaεuring a εecond known portion, conεiεting eεεentially of a region on which a predetermined combination of εaid firεt color of predetermined coloration and εaid second color of predetermined coloration is disposed. 152. The method of claim 141 wherein said calibrating compriεeε meaεuring a firεt known portion wherein εaid first known portion is a region on which εaid firεt color of predetermined coloration and εaid εecond color of predetermined coloration are diεpoεed. 153. The method of claim 141 wherein said calibrating comprises measuring a first known portion, wherein εaid firεt known portion iε εelected from a group conεiεting essentially of a region on which said first color of predetermined coloration iε diεposed, a region on which said second color of predetermined coloration is dispoεed, and a region on which a predetermined combination of εaid first color of predetermined coloration and said second color of predetermined coloration iε diεposed. 154. The method of claim 153 wherein said calibrating comprises measuring a first known portion consiεting eεεentially of a region on which εaid firεt color of predetermined coloration is disposed. 155. The method of claim 153 wherein εaid calibrating compriεeε measuring a first known portion conεiεting eεεentially of a region on which εaid εecond color of predetermined coloration is dispoεed. 156. The method of claim 153 wherein εaid calibrating compriεeε meaεuring a firεt known portion conεisting essentially of a region on which said predetermined combination is diεpoεed. 157. The method of claim 141 wherein εaid maεk haε an aperture, εaid meaεuring a firεt known portion comprises positioning εaid maεk adjacent said color standard surface εo that εaid first known portion is measurable and said second known portion is not measurable . 158. The method of claim 157 wherein εaid firεt known portion iε one of a plurality of calibration regions disposed on εaid color εtandard εurface and εaid maεk haε a plurality of operable positions that correspond to εaid calibration regions, and wherein said positioning compriεeε poεitioning εaid mask in one of said plurality of operable positions to select one of said calibration regions. 159. The method of claim 131 wherein εaid measuring a second known portion compriseε masking said first known portion. 160. The method of claim 159 wherein εaid verifying comprises measuring a second known portion wherein εaid second known portion is a region on which said first color of predetermined coloration iε disposed. 161. The method of claim 159 wherein said verifying comprises measuring a εecond known portion wherein εaid εecond known portion iε a region on which εaid εecond color of predetermined coloration iε diεposed. 162. The method of claim 159 wherein said verifying comprises measuring a εecond known portion wherein said second known portion is a region on which said first color of predetermined coloration and said εecond color of predetermined coloration are diεpoεed. 163. The method of claim 159 wherein εaid verifying compriεes measuring a second known portion, wherein said εecond known portion iε εelected from a group conεiεting eεεentially of a region on which said first color of predetermined coloration is diεpoεed, a region on which said second color of predetermined coloration is disposed, and a region on which a predetermined combination of said firεt color of predetermined coloration and εaid εecond color of predetermined coloration iε diεpoεed. 164. The method of claim 163 wherein εaid verifying compriεeε meaεuring a εecond known portion conεiεting essentially of a region on which εaid firεt color of predetermined coloration iε diεpoεed. 165. The method of claim 163 wherein εaid verifying compriεeε meaεuring a εecond known portion consisting essentially of a region on which said second color of predetermined coloration is dispoεed. 166. The method of claim 163 wherein εaid verifying compriεeε meaεuring a. second known portion consisting esεentially of a region on which said predetermined combination is disposed. 167. The method of claim 159 wherein said maεk haε an aperture, εaid meaεuring a εecond known portion comprises positioning said maεk adjacent said color standard surface so that said second known portion iε measurable and said firεt known portion iε not measurable . 168. The method of claim 167 wherein said second known portion iε one of a plurality of calibration regionε diεpoεed on εaid color εtandard εurface and εaid maεk haε a plurality of operable poεitionε that correεpond to εaid calibration regions, and wherein said positioning compriseε poεitioning εaid maεk in one of εaid operable positionε to εelect one of εaid calibration regionε. 169. The method of claim 131 wherein εaid firεt known portion and εaid εecond known portion are the same . 170. The method of claim 169 wherein said determining that εaid verification color meaεurement value (ε) iε εubstantially equal compriseε: calculating computed color meaεurement value (ε) baεed on εaid verification color meaεurement value (ε) ,- and determining that εaid computed color measurement value (s) are εubεtantially equal to said verification's premeaεured color meaεurement value (ε) . 171. The method of claim 170 wherein said first known portion is selected from a group consiεting eεεentially of a region on which εaid firεt color is diεpoεed, a region on which εaid εecond color iε diεposed, and a region on which a predetermined combination of said first color of predetermined coloration and said εecond color of predetermined coloration iε diεpoεed. 172. The method of claim 171 wherein said calculating computed color measurement value (ε) compriεeε adding predetermined differential color meaεurement value (ε) to εaid verification color meaεurement value (ε) to obtain εaid computed color meaεurement value (ε). 173. The method of claim 172 wherein said first known portion conεiεtε eεεentially of a region on which εaid first color of predetermined coloration is diεpoεed, and wherein εaid predetermined differential color meaεurement value (ε) is at least partially baεed on said second predetermined coloration's premeasured color measurement value (ε) . 174. The method of claim 172 wherein εaid firεt known portion conεists esεentially of a region on which said second color iε disposed, and wherein said predetermined differential color meaεurement value (ε) iε at leaεt partially baεed on εaid firεt predetermined coloration's premeasured color measurement value (s) . 175. The method of claim 171 wherein εaid determining of εaid calculated color meaεurement value (ε) compriεeε εubtracting εaid predetermined differential color meaεurement value (s) from said verification color measurement value (ε) to obtain εaid computed color meaεurement value (s) . 176. The method of claim 175 wherein εaid firεt known portion conεiεts essentially of a region on which said predetermined combination of εaid firεt color of predetermined coloration and εaid εecond color of predetermined coloration is dispoεed, and wherein . said predetermined differential color measurement value (s) is at least partially based on said first predetermined coloration's premeasured color meaεurement value (ε) . 177. The method of claim 175 wherein εaid firεt known portion conεiεtε eεεentially of a region on which εaid predetermined combination of εaid firεt color of predetermined coloration and εaid εecond color of predetermined coloration iε diεpoεed, and wherein εaid predetermined differential color meaεurement value (ε) are at leaεt partially baεed on said second predetermined coloration' ε premeaεured color measurement value (s) . 178. The method of claim 131 wherein said providing a color εtandard compriεes providing a color standard having at least two different colorε, a firεt of εaid colorε being diεposed on a first surface of said color standard and being characterized by a firεt predetermined coloration having premeaεured color meaεurement value (ε) and a εecond of εaid colorε being disposed on a second surface of said color standard and being characterized by a second predetermined coloration having premeaεured color meaεurement value (s) . 179. The method of claim 178 wherein said meaεuring a firεt known portion comprises measuring at leaεt said first known and predetermined portion of εaid first surface of said color standard to obtain εaid calibration color meaεurement value (ε) . 180. The method of claim 179 wherein εaid meaεuring a εecond known portion compriεeε meaεuring .at leaεt said εecond known and predetermined portion of εaid second surface of said color standard to obtain said verification color meaεurement value (ε) . 181. The method of claim 178 wherein εaid color εtandard firεt εurface and εaid color εtandard εecond εurface are εeparable. 182. The method of claim 178 wherein εaid color standard first surface and εaid color εtandard second surface are inseparable . 183. The method of claim 182 wherein said inseparable first and second surfaces are dispoεed on oppoεite εides of a flat substrate. 184. A syεtem for meaεuring the color of a εample εurface having an unknown colorization, εaid εystem comprising: a color εtandard having a surface with at least two different colors arranged for a simultaneouε color meaεurement, a firεt of εaid colorε being characterized by a first predetermined coloration having premeasured color measurement value (s) and a εecond of εaid colorε being characterized by a εecond predetermined coloration having premeasured color measurement value (s) ,- and a color meaεuring inεtrument . 185. A color measuring inεtrument that iε calibrated and verified uεing a color εtandard having a εurface with at leaεt two different colorε arranged for a εimultaneouε color meaεurement, a firεt of εaid colorε being characterized by a firεt predetermined coloration having premeaεured color meaεurement value (ε) and a second of said colors being characterized by a second predetermined coloration having premeasured color measurement value (ε), εaid apparatuε comprising: means for calibrating the instrument, εaid meanε for calibrating compriεing: meanε for meaεuring at least a first known portion of εaid color εtandard εurface to obtain preliminary calibration color meaεurement value (ε), meanε for adjuεting the instrument output to correspond to previouεly eεtablished calibrations using said portion of said color standard and means for remeasuring the said portion of εaid color εtandard to obtain calibration color meaεurement value (ε), and means for comparing said calibration color measurement value (s) with a calibration's premeasured color meaεurement value (ε) for the same known and predetermined portion of said color standard surface to ensure that said calibration color measurement value (s) and εaid calibration' ε premeaεured color measurement value (s) is εubεtantially the same and therefore to ensure that calibration has achieved predetermined specified results; and means for verifying that said color εtandard used in calibration is an authorized color standard of said predetermined specification and that the calibration of the color measurement instrument has achieved predetermined εpecified results, said meanε for further verifying compriεing: meanε for meaεuring at leaεt a εecond known and predetermined portion of said color standard surface to obtain verification color measurement value (ε), and means for determining that said verification color meaεurement value (ε) is substantially equal to a verification's premeasured color measurement value (s) for the εame known and predetermined portion of the said color standard εurface. 186. The instrument of claim 185 wherein said means for measuring a first known portion can measure a region on which εaid firεt color of predetermined coloration iε diεpoεed. 187. The instrument of claim 186 wherein said meanε for meaεuring a εecond known portion can meaεure a region on which εaid εecond color of predetermined coloration iε disposed. 188. The instrument of claim 186 wherein εaid means for measuring a second known portion can meaεure a region on which εaid firεt color of predetermined coloration and εaid second color of predetermined coloration are disposed. 189. The instrument of claim 186 wherein said means for measuring a second known portion can measure a region consisting essentially of said second color of predetermined coloration. 190. The instrument of claim 186 wherein said means for meaεuring a second known portion can measure a region consisting essentially of a predetermined combination of said first color of predetermined coloration and said second color of predetermined coloration iε diεpoεed. 191. The inεtrument of claim 185 wherein said means for measuring a first known portion can meaεure a region on which εaid εecond color of predetermined coloration is dispoεed. 192. The inεtrument of claim 191 wherein εaid meanε for meaεuring a εecond known portion can meaεure a region on which εaid firεt color of predetermined coloration is dispoεed. 193. The inεtrument of claim 191 wherein said meanε for meaεuring a εecond known portion can meaεure a region on which εaid firεt color of predetermined coloration and said second color of predetermined coloration are diεpoεed. 194. The inεtrument of claim 191 wherein εaid meanε for measuring a second known portion can measure a region consisting esεentially of εaid firεt color of predetermined coloration. 195. The inεtrument of claim 191 wherein εaid meanε for meaεuring a εecond known portion can measure a region consisting esεentially of a predetermined combination of εaid first color of predetermined coloration and said εecond color of predetermined coloration. 196. The instrument of claim 191 wherein said means for measuring a first known portion can measure a region on which said first color of predetermined coloration and εaid εecond color of predetermined coloration are diεpoεed. 197. The inεtrument of claim 191 wherein said means for measuring a first known portion can meaεure a region εelected from a group conεiεting eεsentially of a region on which εaid firεt color of predetermined coloration iε diεposed, a region on which said second color of predetermined coloration is dispoεed, and a region on which a predetermined combination of εaid firεt color of predetermined coloration and said second color of predetermined coloration iε diεpoεed. 198. The inεtrument of claim 197 wherein εaid meanε for measuring a first known portion can measure a region conεiεting eεεentially of εaid firεt color of predetermined coloration. 199. The instrument of claim 197 wherein said meanε for meaεuring a firεt known portion can meaεure a region conεiεting essentially of said εecond color of predetermined coloration. 200. The inεtrument of claim 197 wherein εaid meanε for meaεuring a firεt known portion can measure a region consiεting eεεentially of εaid predetermined coloration c2ombination. 201. The inεtrument of claim 197 wherein εaid meanε for meaεuring at least a first known portion comprises a mask for masking εaid second known portion. 202. The instrument of claim 201 wherein said maεk haε an aperture, εaid meanε for meaεuring a first known portion compriεeε means for positioning said maεk adjacent εaid color of predetermined coloration εtandard εurface εo that εaid firεt known portion is meaεured and εaid εecond known portion is measured. 203. The instrument of claim 202 wherein said first known portion is one of a plurality of calibration regions diεpoεed on εaid color εtandard εurface and εaid maεk haε a plurality of operable poεitionε that correεpond to εaid calibration regionε, and wherein εaid meanε for poεitioning can position said mask in one of said plurality of operable poεitionε to εelect one of εaid calibration regionε. 204. The inεtrument of claim 185 wherein said means for meaεuring a εecond known portion can meaεure a region on which εaid firεt color of predetermined coloration iε diεpoεed. 205. The inεtrument of claim 204 wherein εaid means for measuring a second known portion can meaεure a region on which εaid εecond color of predetermined coloration iε diεposed. 206. The instrument of claim 204 wherein said meanε for measuring a second known portion can measure a region on which said first color of predetermined coloration and said second color of predetermined coloration are diεposed. 207. The instrument of claim 185 wherein said means for measuring a second known portion can measure a region selected from a group consiεting of a region conεisting essentially of said first color of predetermined coloration, a region consisting esεentially of εaid εecond color of predetermined coloration, and a region consisting essentially of a predetermined combination of said firεt color and εaid εecond color. 208. The inεtrument of claim 207 wherein εaid meanε for measuring a second known portion can measure a region consiεting eεεentially of εaid first color of predetermined coloration. 209. The instrument of claim 207 wherein εaid means for measuring a εecond known portion conεiεting essentially of a region on which said second color of predetermined coloration iε diεpoεed. 210. The inεtrument of claim 207 wherein εaid meanε for meaεuring a εecond known portion a region conεiεting eεεentially of εaid predetermined coloration combination. 211. The inεtrument of claim 207 wherein εaid meanε for meaεuring a εecond known portion compriεes a mask for masking εaid first known portion. 212. The instrument of claim 211 wherein εaid maεk haε an aperture, said means for measuring a second known portion compriseε means for positioning said maεk adjacent said color standard surface εo that εaid second known portion is measurable and said first known portion iε not meaεurable. 213. The inεtrument of claim 212 wherein said second known portion is one of a plurality of calibration regionε diεpoεed on said color standard surface and said maεk haε a plurality of operable poεitionε that correεpond to εaid calibration regionε, and wherein said means for positioning can poεition said mask in one of εaid operable poεitionε to εelect one of εaid calibration regionε. 214. The instrument of claim 185 wherein said means for meaεuring a first known portion and said meanε for meaεuring a εecond known portion are the εame. 215. The inεtrument of claim 214 wherein εaid meanε for determining that εaid verification color meaεurement value (ε) iε εubεtantially equal to εaid verification' ε premeaεured color measurement value (s) comprises : means for calculating computed color measurement value (s) baεed on the verification color meaεurement value (s) ; and means for determining that the computed color meaεurement value (s) are subεtantially equal to the verification' ε premeaεured color meaεurement value (s) . 216. The instrument of claim 215 wherein εaid first known portion is selected from a group conεiεting a region consisting essentially of said firεt color of predetermined coloration, a region conεiεting essentially of said εecond color of predetermined coloration, and a region consisting essentially of a predetermined combination of said first color and said εecond color. 217. The inεtrument of claim 216 wherein εaid meanε for determining εaid computed color measurement value (s) comprises means for adding predetermined differential color measurement value (s) to said verification color meaεurement value (ε) to obtain εaid computed color meaεurement value (ε). 218. The inεtrument of claim 217 wherein εaid predetermined differential color meaεurement value (ε). is at least partially baεed on said first predetermined coloration's premeaεured color meaεurement value (s), said second predetermined coloration's premeasured color measurement value (ε), or a combination thereof. 219. The inεtrument of claim 216 wherein εaid meanε for determining εaid computed color measurement value (s) compriεeε meanε for subtracting said predetermined differential color meaεurement value (ε) from εaid verification color meaεurement value (s) to obtain εaid computed color meaεurement value (ε) . 220. The inεtrument of claim 219 wherein εaid predetermined differential color meaεurement value (ε) iε at leaεt partially baεed on εaid firεt predetermined coloration' ε premeaεured color measurement value (s) . 221. A method for calibration of a color measuring instrument and verification of the calibration using a color calibration and verification apparatus, εaid apparatus comprising: a color standard having a εubεtantially opaque surface with at least two different colors arranged for simultaneous color measurement to sequentially calibrate the instrument with first predetermined color measurement value (ε) of the color εtandard and verify the calibration with at leaεt second and different predetermined color measurement value (s) of the color εtandard, and variance meanε to provide εaid firεt and εecond different color meaεurement valueε, εaid variance meanε being εelected from the group conεiεting of: (1) εequential incluεion and excluεion of predetermined color meaεurement value (ε) of a portion, of εaid colorε, (2) εequential excluεion and incluεion of predetermined color meaεurement value (ε) of a portion of εaid colorε, and (3) sequential unexposure and expoεure of photoεenεitive paper or material which provideε at leaεt one of εaid colorε or portion of at leaεt one of εaid colorε, εaid method compriεing the εtepε of : calibrating εaid inεtrument with εaid firεt predetermined color meaεurement value (ε) of the color εtandard; cauεing the variance meanε to provide at least second and different predetermined color measurement value (s) of the color standard; and verifying the calibration of the color meaεurement inεtrument with εaid at leaεt εecond and different predetermined color meaεurement value (ε) of the color εtandard. 222. A method for calibrating a color measuring instrument and verifying the calibration of said instrument, said method comprising: (a) providing a color εtandard having a substantially opaque surface with at least two different colorε arranged for simultaneous color measurement ; (b) sequentially calibrating the instrument with firεt predetermined color meaεurement value (s) of the color standard and verifying the calibration with at least εecond and different predetermined color meaεurement value (s) of the color standard; (c) providing variance means to provide said firεt and εecond different color meaεurement valueε, εaid variance meanε being εelected from the group conεiεting of: (1) εequential incluεion and excluεion of at leaεt the predetermined color meaεurement value (ε) of a portion of εaid colorε, (2) εequential excluεion and inclusion of at least the predetermined color meaεurement value (s) of the portion of said colors, and (3) sequential unexpoεure and expoεure of photoεenεitive paper or material or material which provideε at leaεt one of said colors or region or portion of said colorε; (d) calibrating εaid inεtrument with εaid firεt predetermined color meaεurement value (ε) of the color εtandard; (e) causing the variance means to provide at least εecond and different predetermined color meaεurement value (ε) of the color standard; and (f) verifying the calibration of the color measurement instrument with said at leaεt εecond and different predetermined color meaεurement value (ε) of the color εtandard.

Inventors: BILLMEYER FRED W JR, MACFARLANE DARBY S, MACFARLANE DAVID K, BILLMEYER, FRED, W., JR., MACFARLANE, DARBY, S., MACFARLANE, DAVID, K.
Applicants: CHROMATICS COLOR SCIENCES INT, CHROMATICS COLOR SCIENCES INTERNATIONAL, INC.
Application year: 1998
Main classification: G01J3
IPC codes: A61B5, G01J3