bluuebunny/crossref_metadata_2025_split huggingface dataset:
Colour‐difference measurement: The sensitivity of various instruments compared
Authors: Raggi Andrea , Barbiroli Giancarlo 
Published: June 2007

AbstractBecause of the progress in electronic technology and the increasing importance of colour quality control in various branches of industry, over the last decades several colour‐measuring instruments have been developed, each one with its own design features; the lack of standardization among them might be an obstacle to the spread of colour quality control as a means for product qualification. Colour‐difference measurements taken with 11 different models of spectrophotometers [four with 45 (circumferential)/0 geometry and the others with diffuse geometry] were compared with the aim of analyzing their correlation and dispersion. In order to cover different colour‐space regions, measurements were taken on test panels painted with four saturated basic hue (red, yellow, green, and blue) acrylic products gradually modified by adding white or black paint. Basic statistical analyses made on colour‐difference values (ΔE*ab, ΔL*, Δa*, and Δb*) resulted in a high correlation among the examined instruments, but a certain variability, particularly as far as certain hues are concerned.
Extension of dominant wavelength scale to the full hue cycle and evidence of fundamental color symmetry
Authors: Pridmore Ralph W. 
Published: June 2007

AbstractDominant wavelength is a psychophysical scale presently limited to the spectrum. It is extended into the nonspectrals to designate the hue cycle in a continuous wavelength‐based scale. To omit the fading spectrum ends, the extended scale is based on the limited spectrum of optimum color stimuli (442–613 nm). The hue cycle interval is found by many methods in agreement, e.g., from the spacing of the ideal primaries (additive and subtractive). These were recently defined as the complementary maxima and minima of several visual functions (e.g., saturation/W, spectral sensitivity, λ discrimination, complementary efficiency). Five of these six primaries are spectral, uniformly spaced at (40 ± 4) nm intervals. Interpolating the sixth (531 c magenta) as similarly spaced between adjacent primaries (blue 447 nm and red 607 nm) gives it the dual designation 407/647 as both ends of the cycle, an interval equivalent to 240 nm. Nonspectral hues are numbered serially with wavelength by interpolating green–purple complementary pairs as sinusoidallike spectral pairs. Applying the extended scale to a color circle, the six primaries reveal a sextuple symmetry of (60 ± 2)°. Only these three pairs are both complements and opposites. In a graph (hue cycles as x and y axes) of x + y color‐mixture, loci of constant λ center symmetrically on the RGB primaries near 607, 531, 447 nm. © 1993 John Wiley & Sons, Inc.
The CIE 1931 standard colorimetric observer: Mandatory retirement at age 65?
Authors: Fairchild Mark D. 
Published: June 2007

AbstractThe CIE system of colorimetry has been stretched to applications in industries and technologies that were not even envisioned when it was established in 1931. In general the standard observer has made this stretch gracefully. However, there has been a rash of recent articles in this and other journals suggesting that perhaps it is time to force the standard observer to retire. Often the apparent failings of colorimetry are due to its improper application or unrealistic expectations. This Color Forum reviews the status of the CIE standard observer and suggests that, while improvements are certainly possible, retirement would be premature.
Measuring color‐matching functions. Part II. New data for assessing observer metamerism
Authors: North Amy D. , Fairchild Mark D. 
Published: June 2007

AbstractThe Munsell Color Science Laboratory model and visual colorimeter for collecting color‐matching‐function data were described in Part I of this article. The model and instrument have demonstrated results that correlate well with data collected using the National Research Council of Canada's Trichromator. Color‐matching‐function data for 18 observers and 20 repetitions on a single observer have been obtained using the Munsell Color Science Laboratory visual colorimeter. The variability for the single observer for 20 repetitions over a month's time was found to be similar to the uncertainty of matching within a single measurement session. The variability of the 18 observers was found to be much larger. The results were compared with the CIE Standard Deviate Observer. The variability of the CIE Standard Deviate Observer was on the order of the single observer variability while the multiple observer variability was significantly larger.
Sensitivity loss and adaptation within the short‐wavelength cone pathway
Authors: Finkelstein Marcia A. 
Published: June 2007

AbstractTwo‐color increment threshold data are used to develop a model of sensitivity control in short‐wavelength detection. The model includes two sites of compressive nonlinearity. The first site has the characteristics of the S cones. Their output combines antagonistically with signals from the L and M cones at a second (blue/yellow opponent) stage. The response nonlinearities were examined by measuring thresholds for a 420‐nm probe presented at the onset of flashed fields of 420‐nm, 520‐nm, and 580‐nm light. Adaptive mechanisms of multiplication and subtraction were identified by presenting probe and flash on steady backgrounds of varying intensity. Adaptation partially restores the sensitivity lost to response compression.
Fast algorithm for computing color gamuts
Authors: Inui Masao 
Published: June 2007

AbstractA fast and accurate algorithm for computing color gamuts has been developed. In the form presented here for illustration, color gamuts are computed from the dye amounts of subtractive color mixtures. Based on the one‐to‐one correspondence between dye amount space and color space, the simple four‐step algorithm performs a boundary search in dye amount space and a map over to color space. Application to block dyes and commercial reversal film dyes on a desktop computer demonstrates the algorithm's validity, accuracy, applicability, and exceptional speed. © 1993 John Wiley & Sons, Inc.
Measuring the whiteness of human teeth
Authors: García J. A. , Rubiņo M. , Romero J. , Hita E. 
Published: June 2007

AbstractThis work attempts to determine the best index for measuring the whiteness of human teeth. For this the classifications obtained from various whiteness indices have been compared, using Spearman's correlation coefficient, with the responses of 20 observers judging a group of 20 samples of porcelain teeth. The index which gives the best results is that proposed by the CIE, WIC, although the Z% and the CIELAB color difference ΔE are also adequate for measuring the whiteness of human teeth. © 1993 John Wiley & Sons, Inc.
The “alexandrite effect” in gemstones
Authors: Liu Yan , Shigley James , Fritsch Emmanuel , Hemphill Scott 
Published: June 2007

AbstractThe term “alexandrite effect” is used in gemology to describe a distinct change of color appearance when a gemstone is switched from daylight to incandescent light. Gemstones that exhibit the alexandrite effect can actually be divided into four categories based upon the value of the calculated absolute hue‐angle change of the material under different pairs of illuminants. the alexandrite effect is a non‐color‐constancy phenomenon. It can be explained by a combination of both chromaticity adaptations to the different light sources, and vision system responses to the spectral distribution of the light emitted by alexandrite effect gemstones when they are illuminated alternatively by the different light sources.
On the conditions affecting the contribution of color to brightness perception
Authors: Stalmeier Peep F. M. , de Weert Charles M. M. 
Published: June 2007

AbstractColored stimuli appear to be brighter than an achromatic stimulus of the same luminance as the colored stimuli. We have studied this effect using similarity judgments in a triadic scaling task. Several instructions and stimulus configurations were used. the color sets contained colors at three luminance levels. When subjects are instructed to attend to brightness differences, the contribution of the brightness axis is strongly increased relative to the contribution of the color channels. Moreover, a correction to the color input is necessary when subjects are instructed to attend to brightness similarities between saturated colors. For a fixed adaptation level, the chromatic input is relatively stronger for the lower luminance levels. This correction is absent in all other investigated conditions. the correction found here confirms an earlier report by Fairchild and Pirotta (1991).
Transferring the 45/0 spectral reflectance factor scale
Authors: Reniff Lisa 
Published: June 2007

AbstractThe accuracy of spectrophotometric measurements is limited by the standards that are used to calibrate the instrument. Therefore, the procedure used in transferring the spectral reflectance factor scale from one material to another for use in calibration must induce the minimum amount of error. the Munsell Color Science Laboratory has been transferring the spectral reflectance factor scale to calibration materials using a statistical method to correct for the most pervasive systematic errors in the measurement process. This method is based on a statistical procedure in which a set of systematic spectrophotometric errors are estimated based on the measurement of seven NIST primary standards and corrected in subsequent measurements. the optimization of the spectral reflectance factor scale to NIST standards minimizes the induced error. the average reflectance factor error consistently found between the corrected measurements of the NIST standards and their certificate values have been 0.0006 and the average δab has been on the order of 0.2.
Appearance [Cesia]: Construction of scales by means of spinning disks
Authors: Caivano Jose Luis 
Published: June 2007

AbstractThe name cesia has been proposed for the aspect of appearance that deals with the sensations aroused by differences in the spatial distribution of light. In a previous article, a system ofcesias was presented. This included u notation system and a solid with three dimensions or variables in which the sensations were organized. The aim ofthis article is to report the development of scales of cesia, constructed with the aid ofrotatory disks holding percentages of materials producing the stimuling for the,five primary sensations of cesia. These primary sensations are: transparence, specular reflection, translucence, difuse reflection, and absorption [black]. Different geometries of observation were needed to evaluate the scales. Numerically, they were built using a power function belween the magnitudes of the sensations and the magnitudes of the stimuli. This research refutes the assumptions that the geometric attributes of appearance cannot be organized in a coordinate system and that synthetic stimuli cannot be produced for these attributes just as they are produced for color by the mixture of three lights. © 1994 John Wiley & Sons, Inc.
Metrology, documentary standards, and color specifications for fluorescent materials
Authors: Billmeyer Fred W. 
Published: June 2007

AbstractSome aspects of the metrology of fluorescence are reviewed. ASTM Committee E‐12 on Appearance has written two documentary standards on the instrumental measurement of fluorescent colors. Test Method E 1247 provides two procedures for detecting small amounts of fluorescence that might affect the measurement or use of nominally nonfluorescent materials. Practice E 991 deals with the measurement of specimens meant to be viewed under standard natural daylight, and that, therefore, must be illuminated by a good instrument daylight simulator. Two procedures are given for assessing the suitability of the simulator, and the required instrument geometry is specified. A future ASTM standard is under consideration that would describe methods for correcting the data obtained with another instrument source to the data that would have been obtained with standard daylight illumination. Two groups of standard specifications exist for fluorescent colors used for signaling or safety enhancement. One defines suitable chromaticities for both red and orange colors [among others], but ignores the fact that these colors cannot always be obtained with good lightfastness by use of existing pigments. the other group provides instead a red‐orange specification for which specimens with good lightfastness can be obtained. the relative merits of the two groups are discussed.
Problems in measurement of fluorescent materials
Authors: Gundlach Dietrich , Terstiege Heinz 
Published: June 2007

AbstractFluorescent materials become increasingly important for signalling and warning purposes. Measurement facilities, however, are still very poor. This article reviews the radiometric aspects of fluorescent materials and the measurement of their radiometric and colorimetric characteristics. the precision of colorimeters and one‐monochromator instruments can be improved by applying luminescent reflectance standards, calibrated with a two‐monochromator system. Problems of radiation feedback with sphere geometry and a way to solve this problem with a two‐monochromator system are discussed.
Simulation of daylight for viewing and measuring color
Authors: McCamy C. S. 
Published: June 2007

AbstractFor convenience and reproducibility, daylight is artificially simulated for viewing and measuring colors. Daylight has been standardized in a way that is impractical. the evaluation of fluorescent materials requires simulation of the ultraviolet component of daylight or daylight through a window. Sources for viewing are assessed by spectroradiometry and standard computations. Sources for spectrophotometry may be tested the same way or by measuring radiance factors of fluorescent standards. Better manufacturing methods have improved glass filters. A new filter design method takes account of the spatiospectral nature of the source and affords many degrees of freedom.
The color consultant: A new professional serving architecture today in France
Authors: Prieto Sonia 
Published: June 2007

AbstractIn the twentieth century, interest in color in architecture in Europe has been expressed in several ways. Two periods can be distinguished, characterized by different perceptions of the issue. First, between the 1920s and the outbreak of the Second World War, architects themselves tackled the question of color, either by adopting some sort of polychromy, or on the contrary by excluding it from the design of their buildings. In the second period, in the 1950s, a new form of coloration emerged, this time at the initiative of certain artist‐painters. This was the most significant step in terms of social, even utilitarian, character (but it should not be confused with another phenomenon linked to the manifestation of color, the mural). the new step was taken above all in France, where some artists preferred to apply their sensibility and experience to constructed space—on a different scale from the traditional scale of the painting. Patient experimental attempts and meticulous research by these few forerunners gave rise to a new profession serving architecture, that of the color consultant. It was with the development of industrial architecture and thanks to the way society was evolving that attention turned to the ambiance of the workplace, and the color consultant could come onto the scene. Previously, other professionals had been active for (or against) color in architecture, and prepared the ground for this specialization. A historical overview, marked by certain events in the 20th century architectural movement, illuminates in this discussion the origins and the need for the new profession. In a more detailed way, the working methods and some realizations of the principal French color consultants are addressed—a presentation that is intended to interest researchers or professionals by providing specific information that, despite its importance, seems to be lacking in specialized publications. © 1995 John Wiley & Sons, Inc.
Quantifying colour appearance. part V. simultaneous contrast
Authors: Luo M. Ronnier , Gao X. W. , Scrivener S. A. R. 
Published: June 2007

AbstractExperiments were carried out to investigate the effect of simultaneous contrast on colour appearance by varying the lightness, colourfulness, and hue of an induction field surrounding a test colour. A total of 814 test/surround combinations were displayed on high‐resolution colour displays. Each was assessed by a panel of five to six observers using a magnitude estimation technique. the results indicate that colours presented on a computer display are affected by simultaneous contrast in a similar way to surface colours. All three colour appearance parameters studied (i.e., lightness, colourfulness, and hue) are affected and these effects are summarized. In general, the results support and add to the findings of the other studies. the Hunt colour appearance model was tested and gave a somewhat poor prediction to this data set. Further modifications are required to improve its performance. © 1995 John Wiley & Sons, Inc.
Linearity and additivity of small color differences
Authors: Witt Klaus 
Published: June 2007

AbstractThe functional relation of visual to colorimetric scaling of small color differences is needed for a realistic interpretation of the perceptual magnitude of a measured color difference. Linearity is usually assumed and differences are expressed in threshold units without adjustment. an experimental plan is described that provides for the application of gray‐scale assessment to visual judgments under controlled parameters. Gray scale and test colors were produced from a two‐component acrylic lacquer system. A green color center (CIE green) was chosen for a first test with color differences extending from the center in the directions of hue, saturation/chroma, and lightness in steps ranging from ‐5 to + 5 thresholds. Thirteen observers made 4 judgments of each of 78 color‐difference pairs. the resulting scales were typically linear but increasing less steeply than threshold stepping; however, Fstatistics showed some inhomogeneous effects. Scales along the main color directions tended slightly to subadditivity. the vector model of color difference better predicted the magnitude of diagonal jumps between two color directions than did the city‐block model. Relations to some recent color‐difference formulae were studied and the CIE TCI‐29 formula was found to be a good predictor for this color center. © 1995 John Wiley & Sons. Inc.
Colorimetry of durable fluorescent retroreflective materials
Authors: Burns David M. , Johnson Norbert L. , Pavelka Lee A. 
Published: June 2007

AbstractThe development of durable daylight fluorescent retroreflective sheetings has led us to investigate some of the factors that influence color measurement of these materials. the colorimetry of retroreflective materials is particularly sensitive to measurement geometry. the added aspect of fluorescence increases the spectral uncertainties, making appearance measurements even more difficult. the visual properties used to describe fluorescent retroreflective materials should include chromaticity, lightness, peak spectral radiance factor, nighttime color, and color stability on exposure. A number of test methods exist for these measurements; however, practical experience in applying these methods to fluorescent materials shows significant variation in the resulting measured values. Colorimetric measurements on commercial instruments using 45/0 (0/45) geometry, a simulated D65 illuminant, and the CIE 2° standard observer yield results that are inadequate for precise quality control of durable fluorescent retroreflective materials. the uncertainty can be reduced by the use of transfer standards, provided that the standard is similar to the sample in both hue and fluorescent emission. Ultimately, the wide availability of commercial 2‐monochromator spectrocolorimeters will be required. © 1995 John Wiley & Sons, Inc.
Enhancing the daytime conspicuity of pedestrians through the usage of fluorescent materials
Authors: Lesley Gary 
Published: June 2007

AbstractThe issue of daytime, pedestrian visibility, especially where occupational activities are involved, can be well served by bringing existing and related knowledge on high‐visibility materials together with new product capabilities. Formulated strategically, this information can beneficially serve the personal safety of our society. This particular form of personal safety involves being seen, most critically, by operators of motorized vehicles. Therefore, the issues of visibility, visibility enhancement, and conspicuity are focused upon through the use of high‐visibility materials. High‐visibility materials include but are not limited to retroreflective forms. In daytime and dusk/dawn conditions, fluorescent‐colored products can serve as high‐visibility materials used to effectively generate enhanced conspicuity. the time has now come to more aggressively research what we may intuitively believe and then apply this knowledge. to more fully grasp what is involved, we must take into account the following: 1. a basic understanding of fluorescence, 2. basic human vision and perception, 3. situations calling for enhanced conspicuity, 4. strategies for use, 5. product development, 6. specfications, guidelines and standards, 7. public education, and awareness. © 1995 John Wiley & Sons, Inc.
Revision of the chroma and hue scales of a nonlinear color‐appearance model
Authors: Nayatani Yoshinobu 
Published: June 2007

AbstractThe following questions were raised to chroma and hue scales of the nonlinear color‐appearance model: 1) significant nonuniformities of the chroma scales for different hues, and 2) deviations of hue scale between the model and the Munsell and the NCS schemes. It was suggested that the problems were caused by the use of the coefficient es(0) proposed by Hunt. Instead of es(0), a new coefficient Es(0) was proposed, which corresponds to the chromatic strengths of spectral colors (including colors on the redpurple locus). By using Es(0), the nonlinear color‐appearance model could predict the hue and chroma scales of the Munsell and the NCS schemes quite nicely. the method in the present study is generally applicable for determining hue and chroma perceptions of object colors irrespective of the color‐appearance model used.
Lightness dependency of chroma scales of a nonlinear color‐appearance model and its latest formulation
Authors: Nayatani Yoshinobu , Sobagaki Hiroaki , Yano Kenjiro Hashimoto Tadashi 
Published: June 2007

AbstractIt has been noticed that the lightness dependency of equal chroma loci of the nonlinear color‐appearance model already reported deviates markedly from that of equal Chroma loci of the Munsell scheme. to solve this problem, the new chroma CN of the model is proposed by applying the correction of lightness LA to the chroma C previously used. the chroma C is now used to predict the saturation of the newly revised model. the introduction of CN improves significantly the agreement of lightness dependency between the model chroma, the Munsell Chroma, and the NCS chromaticness at various lightness levels. the formulation for the revised nonlinear colorappearance model is given in the Appendix.