Color‐naming of M‐cone incremental flashes

To study which hues are associated with brief excitations of foveal middle‐wavelength (M) cones, two highly practiced color‐normal observers (the authors) gave basic color names to 500 and 530 nm increments. The test spots were presented to the fovea and foveola in conditions that included M‐cone isolation. 1° and 3.6 min arc tests were flashed for 200 ms on steady 8.6′, 1°, or 10° monochromatic adapting fields (481, 530, 610, and 630 nm), or on mixtures of these fields, or on a dark field. Tests were flashed at 1, 2, 4, and 8 × thresholds. Field hue had little overall effect. Yellow, green, blue‐green, and blue color‐names were elicited, both for the foveal 1° tests and for 3.6 min tests confined to the S‐cone free foveola. These data add to previous research by showing a contribution of M‐cones to blueness on monochromatic fields, as well as on achromatic fields. Because the 500 and 530 nm tests appear green when presented steadily on these same fields, the M‐cone contribution to blue may well be transitory. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 132–140, 2001     

Equivalent lightness of colored objects at illuminances from the scotopic to the photopic level

Equivalent lightness of four colored objects, blue, green, yellow, and red, was obtained for illuminance levels covering the range 0.01 to 1000 lx by brightness matching to a grey scale. Three field sizes, 20', 1° and 6° arc of visual angle, were investigated. With the smallest size, for which no rod response was expected, the equivalent lightness increased monotonically for incresing illuminance, showing the increasing effect of colorfulness upon brightness. The results obtained with the largest size showed influence from both rods and cones and were interpreted as due to two underlying lightnesses, one lightness based on the achromatic response of rods, cones, or both, and the other lightness based on the chromatic response of cones exhibited as colorfulness.     

Complementary colors theory of color vision: Physiology,color mixture,color constancy and color perception

I describe complementary colors' physiology and functional roles in color vision, in a three‐stage theory (receptor, opponent color, and complementary color stages). 40 specific roles include the complementary structuring of: S and L cones, opponent single cells, cardinal directions, hue cycle structure, hue constancy, trichromatic color mixture, additive/subtractive primaries, two unique hues, color mixture space, uniform hue difference, lightness‐, saturation‐, and wavelength/hue‐discrimination, spectral sensitivity, chromatic adaptation, metamerism, chromatic induction, Helson‐Judd effect, colored shadows, color rendering, warm‐cool colors, brilliance, color harmony, Aristotle's flight of colors, white‐black responsivity, Helmholtz‐Kohlrausch effect, rainbows/halos/glories, dichromatism, spectral‐sharpening, and trimodality of functions (RGB peaks, CMY troughs whose complementarism adapts functions to illuminant). The 40 specific roles fall into 3 general roles: color mixture, color constancy, and color perception. Complementarism evidently structures much of the visual process. Its physiology is evident in complementarism of cones, and opponent single cells in retina, LGN, and cortex. Genetics show our first cones were S and L, which are complementary in daylight D65, giving a standard white to aid chromatic adaptation. M cone later split from L to oppose the nonspectral (red and purple) hues mixed from S+L. Response curves and wavelength peaks of cones L, S, and (S+L), M, closely resemble, and lead to, those of opponent‐color chromatic responses y, b, and r, g, a bimodal system whose summation gives spectral‐sharpened trimodal complementarism (RGB peaks, CMY troughs). Spectral sharpening demands a post‐receptoral, post‐opponent‐colors location, hence a third stage. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011     

Applications of vectorial color

A companion article introduced a set of orthonormal opponent color matching functions (CMFs). That “orthonormal basis” is an expedient for plotting lights in Cohen's logical color space. Indeed, graphing the new CMFs together (as a parametric plot) gives Cohen's invariant locus of unit monochromats (LUM). In this article, the functions and related vector methods are applied to fundamental problems. In signal transmission and propagation‐of‐errors work, it is desirable to describe stimuli by decorrelated components. The orthonormal CMFs inherently do this, and an example is worked out using a large set of color chips. Starting with the orthonormal functions, related functions, such as cone sensitivities, are graphed as directions in color space, showing their intrinsic relationships. Building on work of Tominaga et al., vectorial plots are related to the problem of guessing the illuminant, a step toward a constancy method. The issue of color rendering is clarified when the vectorial compositions of test and reference lights are graphed. A single graph shows the constraint that the total vectors are the same, but also shows the differences in colorimetric terms. Since the LUM summarizes a trichromatic system by a three‐dimensional graph, dichromatic observers can be represented by 2‐D graphs, revealing details in a consistent way. The “fit first method” compares camera with human, applying the Maxwell‐Ives criterion in graphical detail. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011.     

Fit‐first to be tied

This poem summarizes the fit‐first method of camera evaluation described in Jim Worthey's “Applications of vectorial color.” The algorithm works with the locus of unit monochromats (LUM) in camera and CIE color‐matching spaces. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011;     

A comparison of five color order systems

Five color order systems (Munsell Renotations, Munsell Re‐renotations, OSA‐UCS, NCS, and Colorcurve) have been compared by optimizing the powers applied to individual opponent‐color functions. The results indicate general similarities in that powers applied to the red and green functions tend to be closer to 1, while those applied to the blue function and the yellow function are generally smaller. Specifically, there are many individual differences that make each system unique. The results inspire confidence in the veracity of the opponent‐color system methodology. © 2000 John Wiley & Sons, Inc. Col Res Appl, 25, 123–131, 2000     

Lighting,indoor color,buying behavior and time spent in a store

Relationship between a store's lighting and indoor color and the measures of buying and time spent were studied with a study group of 440 men and 478 women who were 20–60 years old (M = 29.3, SD = 10.2). Two types of lighting (soft and bright) and 5 indoor colors (blue, yellow, green, red, and white) were used. Green color and the time spent in the store were statistically significant positive effects on product purchase. Time spent in the store was positively associated with soft lighting conditions, but negatively associated by red indoor color. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011     

Categorical formation of Mandarin color terms at different luminance levels

This study presents the categorical formation of a set of Mandarin color terms on the International Commission on Illumination (CIE) 1931 chromaticity diagram across six luminance levels. This article conducted a study that employed 44 native Mandarin speakers to perform a force–choice sorting task. The Mandarin color terms for sorting were determined by a free‐recall pretest and are consistent with basic color terms proposed by Berlin and Kay. The square‐sampled stimuli were generated by evenly sweeping the x–y diagram of 5, 10, 25, 50, 100, and 170 cd/m² planes. The categorical sorting results and response time (RT) measurements suggest that: (1) the concepts of green, blue, purple, and gray stably exist at most luminance levels. The voting RT for the green, blue, and purple categories is particularly short. (2) Red, orange, yellow, and pink are highly luminance‐dependent; these can be identified without difficulty only at some restricted luminance levels. (3) The chromaticity areas designated as orange, partial yellow, red, and pink are recognized as brown when the luminance level decreases. (4) Brown and gray serve as representations of two distinct tints in the low saturation condition. (5) The location of boundaries between blue and green are remarkably different than those in a similar study that employed Japanese speakers. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011.     

R/G and Y/B opponent-color mechanisms revealed in temporal integration for bichromatically mixed lights

In the present study, the critical durations for temporal integration at theshold were obtained for bichromatically mixed (red/green and yellow/blue) test lights presented against darkness and achromatic backgrounds of different intensities. Critical durations crucially depended on the mixing ratio of the red and green components: it was shortest when red and green components were balanced in intensity canceling chromaticness of both components, and longer for red and green monochromatic lights. This trend was pronounced with backgrounds of higher intensities but was not obvious with dim backgrounds. The results of yellow/blue condition showed that critical durations were shorter when yellow component was dominant, as well as when yellow and blue components were balanced in intensity canceling chromaticness of both components, but when blue monochromatic light was dominant, it was longer than in other mixture conditions and changed less with the elevation of the background intensity. The results were interpreted as demonstraing the red/green and yellow/blue opponet-color mechanism's participation.     

Hue,chroma, and lightness preference in Chinese adults: Age and gender differences

Recent studies have shown cultural differences in color preference. However, the color preference of people in China, which was found to have its own pattern, was yet to be studied in depth. The current study investigated color preference and the associated age and gender differences in an adult national sample (N = 1290) to provide a culture‐specific characteristic of color perception. Participants rated how much they liked each of 31 colors (four chroma‐lightness levels of red, orange, yellow, green, cyan, blue, and purple, plus three achromatic colors). We found a unique saturated color preference pattern characterized by red, cyan, and blue being preferred the most and orange as the least preferred chromatic color. The “red preference” phenomenon was observed in Chinese adults. Light colors were preferred the most in terms of chroma‐lightness level, followed by saturated, muted, and dark colors. The results of a principal component analysis of the 28 chromatic colors showed that blue‐green‐like colors (cool colors) constituted the largest proportion of color preference. The preference for orange and several dark colors increased with age, while that for bluish colors, purple, yellow, white, black, and light colors decreased. In terms of gender, women liked cyan, white, pink, and light colors and disliked red, orange, and dark colors more than men did. Our findings provide new empirical evidence about the color preference of Chinese and may offer some insight into the study of color preference and lay the foundations for future theoretical and practical research.     

Color identification data obtained from photopic to mesopic illuminance levels

To use colors properly as an aid in visual tasks, it is necessary to know how colors are identified under various illuminating environments. In this study color identification was examined under a wide range of illuminances, from photopic to mesopic levels. Fifteen subjects named a color chip using one of the preselected color terms: red, orange, yellow, yellow‐green, green, blue‐green, blue, purple, pink, brown, white, gray, and black. The 256 color chips were selected from value planes of 4, 6, and 8 of the Munsell color space. The illuminance levels tested were 1000, 10, 1, and 0.1 lx. At 1000 lx the color chips were identified consistently by each of the color terms. At 10 lx the pattern of color identification was very similar to that at 1000 lx, though the consistency of the identification evidently declined. At 1 lx great changes in color identification occurred. By 0.1 lx reliable color identification was completely lost, though blue and red responses remained. At the lower illuminances green was replaced with blue, and red, orange, and pink were frequently confused with each other. However, the border between blue and purple was almost constant. These results provide a scientific basis for the appropriate use of colors in various illuminating environments. Also, they are useful for studies in color appearance modeling. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 252–259, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10065     

Site‐specific Protein Cross‐Linking with Genetically Incorporated 3,4‐Dihydroxy‐L‐Phenylalanine

Come together right now with L ‐DOPA : Chemical cross‐linking is widely used to study protein–protein interactions. However, many cross‐linking agents suffer from low reactivity or selectivity. An efficient and selective reaction of site‐specific protein cross‐linking was achieved using genetically incorporated 3,4‐dihydroxy‐L ‐phenylalanine.

     

Additivity failure of chromatic valence in the opponent-color theory

The additivity of flicker responses produced by two different wavelengths λ₁ and λ₂ was investigated for five adapting levels of 560 nm by the summation-index method. A summation-index value of σ of 0.30 was obtained for all conditions employed, confirming the linear property of the achromatic channel. The additivity of unique chromatic responses, red, yellow, green, and blue, was also investigated with the same method. In this case the wavelengths λ₁ and λ₂ were chosen in a spectral region to produce one of the four unique colors and the summation index was measured for the color with the cancellation method. A summation index of 0.30 was found for the green and blue sensations and also for the red sensation if both stimuli were from the same spectral region. A slight additivity failure of the enhancement type was found for pairs λ₁ and λ₂ λ₁ was in the short-wavelength region while λ₂ was in the long-wavelength region. An additivity failure of the same type was found for the yellow chromatic sensation when λ₂ was 607 nm and λ₁ was 570, 550, or 533 nm, the last combination giving a summation index of as much as 0.64. The results imply the existence of two different cones whose responses do not add linearly to yield the yellow sensation.     

Geodesic calculation of color difference formulas and comparison with the munsell color order system

Riemannian metric tensors of color difference formulas are derived from the line elements in a color space. The shortest curve between two points in a color space can be calculated from the metric tensors. This shortest curve is called a geodesic. In this article, the authors present computed geodesic curves and corresponding contours of the CIELAB ( ), the CIELUV ( ), the OSA‐UCS (ΔE_E) and an infinitesimal approximation of the CIEDE2000 (ΔE₀₀) color difference metrics in the CIELAB color space. At a fixed value of lightness L*, geodesic curves originating from the achromatic point and their corresponding contours of the above four formulas in the CIELAB color space can be described as hue geodesics and chroma contours. The Munsell chromas and hue circles at the Munsell values 3, 5, and 7 are compared with computed hue geodesics and chroma contours of these formulas at three different fixed lightness values. It is found that the Munsell chromas and hue circles do not the match the computed hue geodesics and chroma contours of above mentioned formulas at different Munsell values. The results also show that the distribution of color stimuli predicted by the infinitesimal approximation of CIEDE2000 (ΔE₀₀) and the OSA‐UCS (ΔE_E) in the CIELAB color space are in general not better than the conventional CIELAB (ΔE) and CIELUV (ΔE) formulas. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 259–266, 2013     

Back Cover,Volume 99, Issue 3

2015 ACerS Ceramographic Exhibit & Competition Category: OM, 1^st Place

     

Effects of Surface Deactivation of Carbon Black on Thermomechanical Sensitivity of Filler Networks in Rubber Compounds

The strain and thermal dependence of the dynamic mechanical properties of carbon black filler networks underpin the performance of many rubber components. These effects are examined by varying the surface energetics of carbon black. This has a profound influence on the level of flocculation of the carbon black network in the final crosslinked compounds. Filler networks comprised of thermally deactivated carbon blacks are significantly more strain‐sensitive – shifting the onset of the Payne effect to smaller dynamic strains. Using free vibration equipment to precisely probe the thermal sensitivity of the linear viscoelastic properties of the filled compounds, it is shown that carbon black deactivation results in carbon black networks which are more thermally sensitive than corresponding unmodified carbon black networks. Increased thermal dependence of the dynamic moduli results in the appearance of a secondary increase in tan δ as a function of increasing temperature well above the rubber T_g – which is not correlated with any thermal transitions in calorimetric experiments. Such effects are prevalent in the relevant literature for various rubber–filler combinations but their physical origins are often misinterpreted or unexplained. A rationalization of these effects based on the dynamics of the filler network is presented.

     

Use of basic color terms by red–green dichromats: 1. General description

Abstract: In this article we present data comparing red–green dichromats' use of “Basic Color Terms” (BCTs) with that of standard trichromats. In a complementary article (Color Res Appl 2013) we use these data to evaluate two models of the mechanisms underlying dichromats' use of BCTs. There were three groups of observers—trichromats, protanopes, and deuteranopes—that each performed two tasks: “mapping” (which of these are exemplars of X?) and “best exemplar” (which is the best instance of X?), where X took the value of each Spanish BCT. The mapping task results were subjected to multidimensional scaling that revealed that dichromats differ from trichromats in the number and nature of the dimensions needed for describing BCTs' use. Trichromats required three dimensions closely related to the opponent color mechanisms (red–green, yellow–blue) and the light‐dark channel. In contrast, tridimensional solution for dichromats was difficult to interpret, whereas the fit for the bidimensional solution was very good and revealed a chromatic dimension, which did not match any of the trichromatic dimensions, and an achromatic one. There were also some error‐asymmetries (sometimes “A” was the predominant error when choosing exemplars of “B”, but not vice versa) and the groups differed in the frequency of use of some BCTs (e.g., protanopes chose more stimuli as orange than trichromats and deuteranopes). As expected, the best exemplar task produced more correct responses than the mapping task, and for both tasks, “primary” BCTs (black, white, red, green, yellow, and blue) produced better results than “derived” ones (brown, purple, orange, pink, and grey). © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 360–371, 2014     

Equivalent lightness of elderlies investigated by cataract experiencing goggles

People get cataract in their eyes when they age. The color perceived by the senile cataract eyes desaturates because of the environment light that scatters in the eyes by the hazy crystalline lenses. We investigated the effect of the desaturation on brightness of objects in terms of the equivalent lightness , which is composed of the achromatic lightness and the chromatic lightness . If the color desaturates, becomes smaller and consequently becomes smaller in the cataract eyes. with and without cataract experiencing goggles at room illuminances to cover mesopic to photopic level was measured. Red, yellow, green, and blue patches of size 2° × 2° arc of the visual angle were investigated with the direct heterochromatic brightness matching between the color patches and a gray scale. Both took about the same value. with goggles was then transferred to the final where the matching gray scale was observed without goggles to express the equivalent lightness of cataract eyes by the gray scale perceived by normal eyes. with goggles was lower than without goggles by about 10 L* units in all the four colors. This reduction was almost equal to the reduction of L* by the reduced transmittance of the goggles showing that there was no effect of color desaturation. The color appearance in the color patches was measured by the elementary color naming method, and the results clearly showed the color desaturation with goggles implying decrease of . We concluded that the scattered environment light compensated the decrease of to keep the brightness of stimuli unchanged. © 2011 Wiley Periodicals, Inc. Col Res Appl, 38, 267–276, 2013