bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of white point and phosphor set differences of CRT displays
Authors: Engeldrum Peter G. , Ingraham John L. 
Published: June 2007

AbstractThere are a variety of CRT phosphor sets used to display color information. In addition, the white point, achieved when the red, green, and blue phosphors are excited by beam currents corresponding to the maximum digital count for each primary, is not standardized. Displaying a file containing RGB digital values on unlike monitors, with different phosphors and/or white points, would produce different colors. Computer stimulations were conducted to compute the colors for CRTs with different phosphor sets and constant white points and for different white points with contant phosphor sets. Test results demonstrated that CIE‐LAB color differences were larger when the phosphor sets were different. Smaller color differences resulted from differences in white point, assuming a constant phosphor set. Overall average color differences were reasonably represented by a linear relationship to the average color difference between the phosphors. A linear relation was also found between the average color differences and the color differences between the white points. It was concluded that phosphor differences contribute more to color differences, and therefore standardization efforts should focus first on adopting a color phosphor set, and secondly on a white point.
ASTM standards on color‐difference measurements
Authors: Billmeyer Fred W. , Hammond Harry K. 
Published: June 2007

AbstractFor some time, the only documentary standard on color‐difference measurements within the American Society for Testing and Materials (ASTM) has been D 2244, “Method for Calculation of Color Differences from Instrumentally Measured Color Coordinates.” It was developed by ASTM Committee D–1 on Paint and Related Coatings and Materials, and currently includes only the three color–difference equations of particular interest in the paint industry, namely CIELAB, Hunter Lab, and FMC‐2. ASTM Committee E‐12 on Appearance plans to prepare a comprehensive standard, probably a Guide to the Selection and Use of Color‐Difference Equations. It will contain not only the three equations mentioned above but also a number of others. The Guide will also include tutorial discussion on the selection of equations for various color‐difference evaluation purposes. This article documents the history of color‐difference standards within ASTM. It also invites readers to contribute suggestions for material to be included in the proposed Guide.
Color‐appearance model and chromatic‐adaptation transform
Authors: Nayatani Y. , Takahama K. , Sobagaki H. , Hashimoto K. 
Published: June 2007

AbstractA nonlinear color‐appearance model was extended to apply to white and light‐gray background. Based on this extended model, two kinds of chromatic‐adaptation transforms were derived, which correspond to lightness‐chroma match and brightness‐colorfulness match. The chromatic‐adaptation transform for lightness‐chroma match is also an extension of the transform proposed by CIE for further testing. The differences between the two transforms were confirmed by visual observations. The usefulness of a combination of a color‐appearance model and its corresponding chromatic adaptation transform is discussed. In addition, the practical importance of brightness and colorfulness is discussed.
Comparison of color‐appearance models
Authors: Nayatani Yoshinobu , Mori Toshinori , Hashimoto Kenjiro , Takahama Kotaro , Sobagaki Hiroaki 
Published: June 2007

AbstractThe color‐appearance models developed by R. W. G. Hunt (model H) and Y. Nayatoni and his collaborators (model N) are compared. The following color perceptions are analyzed: (1) colorfulness under illuminant C for NCS samples, (2) colorfulness change by changing illuminant C to illuminant A, (3) colorfulness change by changing adaptign illuminance, (4) Helson‐Judd effect on achromatic colors under saturated chromatic illuminants, and (5) brightness and lightness. Special features of each model are made clear. In addition, a deatailed discussion is given on the mechanism introbucing the Helson‐Judd effect and on the model formulations, especially in model H.
Test for a correlation between VΛ and the + y opponent‐channel sensitivity
Authors: Ingling Carl R. , Martinez‐Uriegas Eugenio , Grigsby Scott S. 
Published: June 2007

AbstractRushtion and Baker have shown that the ratio of R to G cones varies between observers. We use this variability to ask if observers, say, who are rich in R‐cone input to the flicker (VΛ) channel, are also likely to be rich in R‐cone input to the long‐wavelength half of the y‐b channel. For the 8 observers tested, there is no correlation between cone inputs to +y and VΛ.
Comparison of the munsell, NCS, DIN, and coloroid colour order systems using the OSA‐UCS model
Authors: Smith N. S. , Whitfield T. W. A. , Wiltshire T. J. 
Published: June 2007

AbstractAn earlier article described the use of a colour notation conversion program to measure the accuracy of the NCS, DIN and OSA‐UCS color atlases. This article describes the application of the same program to compare the perceptual scaling of the Munsell, NCS, DIN, and Coloroid systems with that of the OSA‐UCS system. Five OSA‐UCS cleavage planes were selected which represent a varied but systematic sampling of OSA‐UCS colour space. The samples contained on these planes were converted onto the colour spaces of the Munsell, NCS, DIN and Coloroid systems. The converted points have been displayed graphically for ease of comparison.
The purkinje effect: Some considerations on the interplay of receptoral and postreceptoral mechanisms
Authors: Ronchi Lucia R. 
Published: June 2007

AbstractA heterochromatic brightness or lightness match, established at photopic levels, is not expected to hold at lower adapting luminances. This applies, in particular, to the Purkinje Effect, concerning the red‐blue comparison. The fact that a “blue” stimulus mainly involves the shorter wavelengths favors the interpretation in terms of rod intrusion, coming gradually into play as the eye, pre‐adapted to a photopic level, is becoming adapted to a mesopic or scotopic one. The two experiments described in this paper aim to put into evidence some effects that are likely to be due to postreceptoral mechanisms, and which may confuse the student faced with a practical demonstration of the Purkinje Effect. In particular, we consider the blue lightness enhancement after an abrupt decrease in adapting luminance, and the decay of lightness‐luminance discrepancy of narrow‐band stimuli during the recovery period.
Comparison of reference‐white standards for video display units
Authors: Brill Michael H. , Derefeldt Gunilla 
Published: June 2007

AbstractThere are two common chromaticity standards for video‐display‐unit reference white, one standard at 6500 K correlated color temperature (CCT), called D65 for short, and the other, an industrial standard, at 9300 K CCT. The choice of D65 evolved from the NTSC specification for television receivers based on Illuminant C—an average daylight at 6800 K CCT. Although originally the studio illumination was much redder than D65, modern television cameras operate in daylight, so a daylight white standard is most likely to allow exact color reproduction at the receiver. Hence average daylight is the most natural white point. However, many manufacturers chose 9300 K because the chromatic efficiency of the prevailing blue phosphors was greater than that of red or green phosphors, because viewers did not object to a blue color bias, and because 9300 K was bluer than any of the prevailing ambient illuminations. In the years since the adoption of the 9300‐K standard, these facts underwent some change, and also VDUs came to be used for graphics as well as for television. This paper outlines the reference‐white problem, and suggests a reevaluation of the 9300‐K standard.
Construction of discrimination ellipsoids for surface colors by the method of constant stimuli
Authors: Indow Tarow , Morrison Melvin L. 
Published: June 2007

AbstractFirst, methods to define the region of colors indistinguishable from a standard color are reviewed, both for aperture and surface colors. Then, an algorithm to define discrimination ellipsoids for surface colors in (x,y,l) space is described, where 1 is a function of Y. The data are a set of Pi, the proportion that a comparison stimulus si is judged discriminable from a standard stimulus So (the method of constant stimuli). An ellipsoid is defined around So such that, if the distance between So and si is evaluated by the radius of the ellipsoid in that direction, then that distance is related to Pi in the form of a sigmoid curve (the cumulative normal distribution). The third axis of the ellipsoid is defined to be parallel with the Y axis and hence there are four free parameters. These parameters are estimated using the principles of either chi‐square minimum or maximum likelihood estimation. The algorithm was applied to the data obtained from, respectively, R.M. Rich, D.C. Rich, and Witt and Döring. Results by the present method were compared with their results, which were obtained using different procedures. The method was also applied to the data of Bartleson to test the possibility that the domain of colors called “brown” is ellipsoidal in form; the result was negative. A theoretical discussion on the naure of the sigmoid curve is included.
Structural correspondence between music and color
Authors: Sebba Rachel 
Published: June 2007

AbstractThe article outlines the features that are typical of the attempts to bridge between music and color on the artistic and scientific levels. It emphasizes the importance of clarifying the factors common to color and sound both for the purpose of understanding the communication codes of arts as well as for the development of syntax for expression in colors. The article adopts Gombreich's approach to investigate the connection between music and color through comparison of the relationships between the elements and not through comparison of the elements themselves. The article presents an experiment that examines how the organization of the sounds in a musical piece is expressed in color design: (1) How the overall impression of a piece of music is expressed in the choice of colors and in their reciprocal relationships; (2) What are the characteristics of color scales that were shaped according to a musical scale; and (3) What is the visual effect of a color scheme that was built according to the formation of notes of the musical piece.
Quantifying colour appearance. Part I. Lutchi colour appearance data
Authors: Luo M. Ronnier , Clarke Anthony A. , Rhodes Peter A. , Schappo André , Scrivener Stephen A. R. , Tait Chris J. 
Published: June 2007

AbstractThe work described here forms part of a research project entitled Predictive Perceptual Colour Models. The aim of this project is to develop a colour appearance model capable of predicting changes of colour appearance under various different viewing conditions. This will provide industry with a quantitative measure for assessing the quality of colour reproduction and enable more rapid and accurate proofing simulations in the graphic art industry. A large‐scale experiment has been carried out in which colour appearance was assessed under a wide range of viewing conditions. The parameters studied were (1) D65, D50, white fluorescent, and tungsten light sources, (2) luminance levels of about 40 and 240 cd/m2, (3) five background conditions: white, grey, black, grey with white border, and grey with black border, and (4) two media: luminous colours (displayed on a high‐resolution colour monitor) and nonluminous colours (presented in a viewing cabinet). Each colour was assessed by a panel of six or seven observers using a magnitude estimation method. In total, 43,332 estimations were made, and these form the LUTCHI Colour Appearance Data. Data analysis has been carried out to examine the reliability of the experimental results and to understand the effects of the various viewing parameters studied. (Part II of this article describes how the LUTCHI Colour Appearance Data has been used to test the performance of various colour spaces and models.
Angular reflectance distributions for coloured newsprint
Authors: Gardner James L. , Shaw John E. , Bonham James S. 
Published: June 2007

AbstractAngular distributions of light reflected from coloured paper surfaces have been measured at three wavelengths in the red, green, and blue regions of the spectrum. These distributions are fitted as the sum of cosine and high‐order cosine terms to describe the diffuse and specular components, respectively. The fitted distributions are used to estimate colour errors for various angular separations of illuminating and viewing beams, and are qualitatively described in terms of scattering and absorption in the paper.
Visual determination of suprathreshold color‐difference tolerances using probit analysis
Authors: Berns Roy S. , Alman David H. , Reniff Lisa , Snyder Gregory D. , Balonon‐Rosen Mitchell R. 
Published: June 2007

AbstractAs part of a research program to improve the relationship between visual and numerical color‐difference evaluation for industrial colorimetry, a color‐difference tolerance data set for fitting and testing of color‐difference metrics has been extended to include 156 individual color‐tolerance determinations. These tolerances were designed to sample 19 color centers over a surface color gamut with balanced sampling of lightness and chromaticness differences. The tolerance determination procedures emphasized accurate estimation of population visual color‐difference response and rigorous estimation of tolerance precision. Tolerance accuracy was confirmed by excellent agreement of these results and the majority of previous experiments on five color centers selected for CIE color‐difference evaluations. The average uncertainty of the tolerance determinations was ± 11% of the tolerance value at a 2 ó level (95% confidence interval). The completed data set is suitable for estimating the parameters of color‐difference metrics or testing the performance of such metrics. The color tolerances indicated the systematic lack of uniformity of the CIELAB space, in general agreement with previous experiments. A simple modification of the CIELAB color‐difference metric was shown to account for much of the systematic lack of uniformity.
An evaluation of some tristimulus weights
Authors: Stearns E. I. 
Published: June 2007

AbstractTristimulus values were calculated for the 1964 observer and illuminant D65 for four theoretical specimens, with radiance factor data of 1‐nm bandpass width, by the CIE recommended procedure and used as accurate references. Tristimulus values were then calculated for the same four theoretical specimens with six sets of published weights, with radiance factors assumed to have a bandwidth equal to the measurement interval and the bandpass profile to be triangular. The difference of the wide bandwidth calculated tristimulus values from the reference tristimulus values was considered to be an error and was expressed as CIE L*a*b* color difference.
The chroma sensor® CS‐5: A tradition of improved performance
Authors: Rich Danny C. 
Published: June 2007

AbstractIn a previous article [R. Stanziola, B. Momiroff, H. Hemmendinger, Color Res. Appl. 4, 157–163 (1979)], a new generation of scanning spectrophotometer was described. The new generation instrument contained many improvements to the recording spectrophotometer designed by A. C. Hardy. This article describes the progeny of that generation. Continued improvements in both optics and electronics have been implemented so that the routine performance of the CS‐5 now far exceeds the ability to make and judge colored specimens.
Recommended terminology for matrix R and metamerism
Authors: Fairman Hugh S. 
Published: June 2007

AbstractIn recent years new terminology for metamerism and related phenomena has been put forth. Terms associated with these phenomena are presented in the form of recommendations from ISCC Committee #27: Indices of Metamerism. The terms are given with a definition and where appropriate a symbol is recommended. A subject closely allied to metamerism is Cohen and Kappauf's spectral decomposition theory, often referred to as Matrix R theory. Terms, symbols, and definitions associated with this subject are additionally recommended. The recommendations are made in the interest of uniformity of future practice on the part of writers and users.
Predicting the lightness of chromatic object colors using CIELAB
Authors: Fairchild Mark D. , Pirrotta Elizabeth 
Published: June 2007

AbstractA metric of perceive lightness of object colors, L**, is derived and evaluated. This metric, based on CIELAB parameters, is designed to predict the Helmhltz‐Kohlrausch effect whereby chromatic object colors appear lighter than achromatic object of the some luminance factor. Models were fitted to published data and then tested with results from a new lightness‐matching experiment that is described in this article. The L** metric predicts perceived lightness to within the interobserver variability and provides a simple, practical measure of this appearance attribute.
Toward a more accurate and extensible colorimetry. Part I. Introduction. the visual colorimeter‐spectroradiometer. Experimental results
Authors: Thornton William A. 
Published: June 2007

AbstractA bright ten‐degree split‐field colorimeter is used to study pairs of visually‐matching lights. This colorimeter is coupled by quartz light pipe to a spectroradiometer, and yields accurate absolute spectral power distributions of every viewed light. Six normal human observers use three disparate sets of spectral primaries. In Part I of the article thorough descriptions of the instrument, its calibration, and experimental results are presented. (1) By the Maxwell method, sets of 28 three‐band lights, each light matching a broadband reference‐white light, are obtained. From these sets are found strong and unexpected dependence of perceived brightness per watt on spectral content, and large systematic errors in computed chromaticity (1964 CIE Observer). (2) From sets of white two‐band lights, each matching the broadband reference light, large differences in wavelength of the visually complementary spectral lights, from those indicated by the 1964 CIE chromaticity diagram are found. (3) Sets of Maxwell‐method and maximum‐saturation‐method color matching functions are obtained for each primary‐set and for each observer. (4) Study, at the colorimeter, of perceived brightness of spectral lights in isolation yields three‐component perceived‐brightness‐per‐watt curves like those of Stiles and Crawford of 1933. (5) Perceived brightness of 3‐band white mixtures always increased upon removal of any one of the three spectral components, in agreement with MacAdam's findings of 1950. (6) Visual tests were made of Grassmann's additivity assumption, and of Maxwell spot phenomena. Part II includes discussion of chromaticity and brightness errors and of other aspects of colorimetry problems‐transformation of primaries, structure and shape of the chromaticity diagram, and normalization of color matching functions. Part III gives avenues of possible improvement and general comment.
Perceived lightness of chromatic object colors including highly saturated colors
Authors: Nayatani Yoshinobu , Gomi Yutaka , Kamei Masaaki , Sobagaki Hiroaki , Hashimoto Kenjiro 
Published: June 2007

AbstractA model was formulated for predicting the Helmholtz‐Kohlrausch effect or the Y tristimulus values for chromatic object colors with the same perceived lightness (L/Y ratios). the model was extended from the previous one in Color Res. Appl. 16, 16‐25 (1991), making it possible to estimate the Helmholtz‐Kohlrausch effect on chromatic object colors with any Munsell Value. By analyzing the two experiments by Wyszecki and by Sanders and Wyszecki using the extended model, the model parameters were estimated for each experiment. By using each of the two estimated equations, L/Y ratios for Y = 20.0 were predicted in the whole chromaticity gamut corresponding to the two kinds of experimental results. the derived contour lines for equal L/Y ratios correlated well with those estimated directly from each experimental data. In addition, extrapolated L/Y ratios for spectral colors with Y = 20.0 showed very good agreement with the luminance ratios for equally bright spectral stimuli, so‐called brightness/luminance (B/L) ratios, derived from the luminous efficiency functions Vb,2(Λ) by CIE TC 1‐02 and Vjudd(Λ) proposed by D. B. Judd.
Munsell value as explicit functions of CIE luminance factor
Authors: McCamy C. S. 
Published: June 2007

AbstractEquations are given to compute Munsell value from a CIE luminance factor Y. The equations are a very accurate, though not mathematically exact, inversion of the fifth‐order equation adopted by the Optical Society of America as the practical definition of Munsell value. The maximum error in Munsell value is 0.0035. The equations have been employed by the Committee on Appearance of the American Society for Testing and Materials.
Discrimination of colours presented against different coloured backgrounds
Authors: McFadden Sharon 
Published: June 2007

AbstractColour electronic displays are being used increasingly for information presentation in a wide range of applications. A prerequisite to the effective use of colour coding is that the colours be discriminable under all of the conditions in which the display will be used. For applications such as radar, medical imaging, or electronic charts, different coloured areas may be juxtaposed and coloured symbols superimposed on a multicoloured background. Under such conditions, the colours in the display may affect the appearance and discriminability of each other. the present article examines the extent to which a set of colours that is clearly distinguishable when presented against a uniform background might be confused when the members are presented against differently coloured backgrounds. This was achieved by measuring the range of chromaticities, presented against a grey background, that would be confused with each of the test colours when they were presented against different chromatic surrounds. the findings were used to derive the characteristics of sets of colours that should be discriminable in a complex display.
Numerical methods for colorimetric calculations: A comparison of integration methods
Authors: Smith Brent , Spiekermann Charles , Sember Robert 
Published: June 2007

AbstractNumerical methods for estimating colorimetric integrals using various data intervals are reviewed. Accuracy of Newton‐Cotes and Gaussian numerical integration algorithms are compared. Tables of calorimetric data for performing Gauss‐Legendre integration are presented. Appropriate numerical examples are presented and applicability to general and special cases is discussed. the B‐spline method of integration is presented. Errors of integration are quantified and discussed. © 1992 John Wiley & Sons, Inc.
A colour notation conversion program revisited
Authors: Smith N. S. 
Published: June 2007

AbstractDetails of an expanded and improved computer program for the interconversion of colour notations are presented. This article describes the inclusion of the Colorcurve, SCA 2541, and HunterLab systems, expansion of the DIN and RAL implements, extension of the NCS aim point database, improvements to the OSA‐UCS and Coloroid conversion algorithms, a direct spectral curve input facility, and the inclusion of CIELAB, CIELUV, HunterLab, CMC[1:1], FMC‐1, and FMC‐2 colourdifference formulas. © 1992 John Wiley & Sons, Inc.