Hue Steps Research Articles

"Warm," "cool," and the colors.

Participants judged affective cooler/warmer gradients around a 12-step color circle. Each pair of adjacent colors was presented twice (left-right reversed), all in random order. Participants readily performed the task, but their settings do not correlate very well. Individual responses were compared with a small number of canonical templates. For a little less than one-half of the participants responses or judgements correlate with such a template. We find a warm pole (in the orange environment) and a cool pole (in the teal environment) connected with two tracks that tend to have one or more gaps or weak, even inverted links. We conclude that the common artistic cool-warm polarity is only weakly reflected in responses of our observers. If it does, the observers apparently use categorical warm and cool poles and may be uncertain in relating adjacent hue steps along the 12-step color circle.

Perceptual and categorical processing and representation in color categorization

We used fMRI to dissociate decisional and perceptual functions in color categorization. Participants viewed sequences of colored squares which varied in perceptual distance (0, 1 or 2 hue steps) and color (green, blue) and then judged whether one or two colors were present. Occipital, caudate, and anterior insula regions were active when more than one hue was presented, indicating a role in perceptual processing and attentional monitoring. Dorsolateral prefrontal cortex showed greater activity when two colors were present than a single color, indicating a role in coding color category. Cognitive control regions of the intraparietal sulcus and presupplementary motor area were sensitive to the interaction of decision and distance in perceptual space, indicating a role in combining these functions during decision making. These results support theories that colors are represented categorically at high levels of the cognitive hierarchy, and that visual cortex is sensitive to hue rather than color category.

Colour Order.

Scrambled hue circles with a resolution ranging from 6 steps to 60 steps were presented on a varicoloured background. The hue steps were presented as mutually non-contiguous “chips,” small circular disks, placed uniformly on a large circle. The task was to sort the chips with respect to their hue. Participants generally manage to sort a 24-step hue circle faultlessly but commit many ordering reversals (also of several steps, up to five) on sorting a 60-step hue circle. The pattern of local reversals of chips depends on the hue region. The findings are relevant for the design of user interfaces for various types of applications, such as colour pickers or graphical design, that rely on rgb screen colours as the available palette.

Age and gender effects on perceptual color scaling using triadic comparisons.

We examined age and gender as possible determinants of individual differences in triadic judgments of color dissimilarity. Seventy triads were constructed from 21 equal-lightness Munsell samples, at equal hue steps, forming a rough ellipse in the CIE-LAB plane, and presented to 51 males and 53 females (half young, half elderly adults) who indicated each triad's "odd one out." Principal component analysis followed by multidimensional scaling (MDS) revealed group differences in judgment reliability, with better performance for female and younger groups. Gender differences in color similarity were more pronounced with age, and specific to sectors of the color circle, arguably involving the use of conventional knowledge of color relationships. Maximum-likelihood MDS and inspection of specific triads allowed a more detailed description of these differences.

Physichochemical Properties and Trace Elements of Soils in Mambilla Plateau of Northeastern Nigeria

The soil samples from Mambila Plateau were analyzed to determine the physicochemical properties of elements present by energy dispersive X-Ray Fluorescence. The physical and chemical parameters determined were colour, pH, electrical conductivity, specific gravity and elemental identifications of Cr2O3, CuO, NiO and V2O5 respectively. The pH values for soils of the study area are high between 3.96-4.30 being acidic, electrical conductivity values ranged from 81.79 – 238 mS/cm with higher electrical conductivity value at N1 having 238 mS/cm and lower electrical conductivity at S1 81.79 uS/cm respectively. The soil are yellow, red and gray; with hue steps of 2.5YR, 5YR, 7.5YR, and 10YR, a step values between 3-7 and the chroma range of 1- 6. The specific gravity which also is the relative density range from 2.00-2.50. The percentage elemental contents identified for trace elements decreased in the order V2O5 > Cr2O3 >NiO > CuO. The highest percentage concentration of element found was V2O5 at N4 0.29% while, CuO showed minimum concentration of 0.01%. The entire soils indicated high acidity levels due to the pH results tested, with spatial variation of the elements oxides contents higher at N1, N2, N3, N4, and decreasing through E1, E2, E3 and E4 to S1, S2, S3 and S4 at lower concentrations.

Event-related potentials reveal linguistic suppression effect but not enhancement effect on categorical perception of color.

The present study used the event-related potential technique to investigate the nature of linguistic effect on color perception. Four types of stimuli based on hue differences between a target color and a preceding color were used: zero hue step within-category color (0-WC); one hue step within-category color (1-WC); one hue step between-category color (1-BC); and two hue step between-category color (2-BC). The ERP results showed no significant effect of stimulus type in the 100-200 ms time window. However, in the 200-350 ms time window, ERP responses to 1-WC target color overlapped with that to 0-WC target color for right visual field (RVF) but not left visual field (LVF) presentation. For the 1-BC condition, ERP amplitudes were comparable in the two visual fields, both being significantly different from the 0-WC condition. The 2-BC condition showed the same pattern as the 1-BC condition. These results suggest that the categorical perception of color in RVF is due to linguistic suppression on within-category color discrimination but not between-category color enhancement, and that the effect is independent of early perceptual processes.

Color constancy investigated via partial hue-matching

Each hue is believed to be made up of the four component hues (yellow, blue, red, and green). A hue consisting of just one component hue is called unitary (or unique). A new technique--partial hue-matching--has been used to reveal the component and unitary hues for a sample of 32 Munsell papers, which were illuminated by neutral, yellow, blue, green, and red lights and assessed by four normal trichromatic observers. The same set of four component hues has been found under both the neutral and the chromatic illuminations for all of the observers. On average, more than 87% of the papers containing a particular component hue under the neutral illumination also have this component hue when lit by the chromatic lights. However, only a quarter of the papers perceived as unitary under the neutral illumination continues being perceived as unitary under all of the chromatic illuminations. In other words, most unitary colors shift along the hue circle due to change in an illuminant's chromaticity. Still, this shift of unitary colors is relatively small: On average, it does not exceed one Munsell hue step.

How well are color components of samples of the Natural Color System estimated?

The aim of this study was to determine how accurately color-normal subjects that have received basic information about, but do not have practical experience with, the Natural Color System (NCS) can estimate the Heringian components of a representative selection of samples. Twenty-five color-normal subjects, taking part in two trials with at least a 24 h gap between assessments, selected four samples representing individual unique hues (uHs) from a set of 40 highly chromatic NCS samples on a rotatable tray. The samples selected for assessment of components were displayed to the subjects who estimated the hue components of 16 high-chroma samples, hue and white/black components of 16 tonal color samples, and three achromatic samples with different blackness values. Variability in selection of samples representing uHs as well as the relationship between the subjects' estimates of unique hue components and the defined values of the system was obtained. It was found that hues alone are easier to correctly estimate than hues together with white and black and that the components of colors of higher chroma are easier to estimate accurately than those of lower chroma. It was also found that, for R and G, the mean uH choices of subjects differed very little from the NCS's R and G, whereas selections for yellow and blue deviated, the former by 1.22 hue steps (slightly greener than G90Y), and the latter by 1.36 hue steps (represented approximately by R85B). This may impact the accuracy of color models that employ NCS unique hues.

Elucidating the effect of yellow illumination on color confusion in the semiconductor-related manufacturing industry

This study investigates how yellow lighting and white lighting affect color confusion in contrast with how sunlight does by using the Farnsworth–Munsell 100 Hue Test System (FM100). Forty college students with normal color vision are enrolled in this study. The experimental setup involves ceiling lighting at a 90° angle on the FM100 with an illuminance of 550 lx, in which the subjects view the FM100 at a 45° angle. All color chips of the FM100 that are fully discriminable under sunlight are arranged in a color circle (FM100 color circle) with equal hue steps resembling those of a 100 Munsell hue circle. Under colored lighting, however, colors may be undistinguishable, resulting in the misplacement of some of the color chips. Color confusion is then determined by counting the number of times a color chip is misplaced, which is called an error score. All error scores are plotted on the FM100 color circle, which is called the color error sheet, to reveal the range and severity of color confusion due to the colored lighting. Experimental results indicate that, although yellow lighting significantly introduces color confusion, white lighting does not. Additionally, yellow lighting does not cause serious impairment in distinguishing between the yellow (its own color) and blue colors (complementary of yellow), but causes significant impairment in distinguishing between the green and red colors. On the error scoring sheet, both the two nonconfusion series and the two confusion series are complementary and orthogonal. This observation allows us to postulate that, although colored lighting does not cause significant impairment in distinguishing between its own complementary colors, it does between its orthogonal colors. © 2010 Wiley Periodicals, Inc.

Correction of a calibration scale for the rapid visual semiquantitative determination of phosphate ions in agricultural samples

A procedure was developed of fabricating a colored calibration scale for determining phosphate ions in aqueous solutions. The procedure is suitable for correcting hue steps depending on the analytical range of phosphate ions. A rapid procedure was proposed for visual testing in a blister cell with a bulk mixture of dry reagents. A test effect was observed immediately after the cell was opened and several drops of a test solution were added. Mixture compositions were developed for the visual determination of phosphate ions in a concentration range of 0.5–80 mg/L by the formation and reduction of phosphomolybdic acid using auxiliary reagents.

Focal colors and unique hues

Unique hues, as recently determined by 40 observers using Munsell color chips, have been compared to published information on focal hues. While there is good agreement in the case of three hues, there is a significant disagreement (nearly 4 Munsell hue steps) in the case of green. An experiment was performed using mostly identical observers, identical color chips, and identical viewing conditions to have 40 observers determine their focal green hue. While their average unique green hue is located at Munsell Hue 2.75 BG, their average focal green is located at 2.5G, thus being in agreement with the average World Color Survey focal green. The result points to different concepts of the observers for unique green and focal green. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 171–172, 2001

Determination of unique hues using Munsell color chips

Forty observers determined their unique hues from arrays of Munsell chips in a standard surround under artificial daylight. There was some discrepancy in the results of males and females. Essentially no variability due to age of observer was found. The standard deviation around the total mean was less than 1 Munsell 40 hue step. Simple linear opponent-color a and b values were calculated. The ranges were found to straddle in all but the red color the system axes for the CIE 2°observer, but not for the 10°observer. NCS unique hues determined at similar chroma and lightness values fell in all cases within the ranges. The shifts in cross-over wavelengths of the color-matching functions necessary to match the extreme range values were determined to be between 6–11 nm. The results provide support for an opponent-color system based on subtractions of color-matching functions. They also point to significant variation in color normal observers. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 61–66, 2001

Towards an improved uniform color space

Analysis of the Munsell, the OSA-UCS, and the NCS systems shows that the idea, originally introduced with the Adams–Nickerson color space and difference formula, that the Munsell value function not only applies to the tristimulus value Y but also to X and Z, is inaccurate. For all three systems, different power functions are required for X and Z. In the case of Z, different powers are needed for the yellow and blue halves. An additional correction is required for the curvature of the constant hue lines of blue colors. New a and b formulas are introduced that correct these shortcomings of CIELAB. In a hue scaling experiment with Munsell chips, the Munsell hue scale was found inaccurate, and a different number of equal-sized hue steps was found in some of the four quadrants. The implications for color difference calculation are discussed. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 253–265, 1999

Attempt for Quantitative Evaluation of Cool-Warm Color Image.

We attempted to analyze quantitatively the cool-warm feeling of color one of the most fundamental affections, in terms of colorimetric value which is supposed to correlate with the affective tone of color. We performed a visual experiment where either “cool” or “warm” was to be selected from the specimens selected systematically in the color space. The results confirmed that the cool-warm feeling was affected by hue and brightness rather than by hue and chroma. The visual evaluation was compared with the hue and brightness calculated from the colorimetric values, and the following empirical formula was found to represent the cool-warm indices (CW), CW=aBr-80 where Br denotes the brightness value. The coefficient a is given by a=20 {cos (π×ΔH5YR/50)+1} where ΔH5YR is the Munsell hue step from 5YR (0_??_ΔH5YR_??_50). The index CW is in the range from -100 to 100, and the value of its correlation coefficient with visual evaluations was found to be higher than 0.92.

Setting up acceptability tolerances: A case study

AbstractCurrent acceptance of goods for color by the United States Army depends on visual comparison against a standard and as many as eight limit samples. The Army wished to have a numerical method of setting color tolerances to be used with instrumental measurement. Preliminary work with the standards and limit samples indicated that acceptability ellipsoids oriented in the hue, chroma, and lightness directions in CIELAB color space should be set up. To establish the tolerances, we selected pairs of samples from a large number of previous submissions by industry. These pairs represented four graduated lightness steps, four graduated chroma steps, and four graduated hue steps. Six observers looked at each pair ten times, randomly interspersed with other pairs, and issued a pass‐or‐fail judgment each time. From these data we established lightness, chroma, and hue tolerance limits. For an olive green and a tan shade, these tolerances were roughly in the ratio 3:2:1; for a dark blue, the ratios were roughly 2:2:1. We wrote simple equations that can be used in order to determine quickly whether a sample passes or fails.

CONSTITUTION OF THE DEPTH VALUE <i>C</i><sup>*</sup> FROM THE THREE ATTRIBUTES OF COLOR

Author has already proposed the depth value C* as a numerical expression of tinctorial strength for dyeings. Though C* value can be calculated easily from the least reflectance of color, the constitution of the three attributes of C* has not yet been clear.For further understanding of the colorimetric meaning about C* value, it is necessary to clarify the relation between C* value and the three attributes of color.Through the analysis of C* values measured on the standard color chips arranged according to the Munsell system, the following equations were obtained. where, C*: depth value C: Munsell Chroma V: Munsell Value tanH°: hue coefficient to multiply the chroma ΔH5P: hue step from 5P on Munsell hue circle

Influence of Red and Blue Pre-Adaptation on Hue Matching of Purple Samples*

This experiment was designed to show the effect, if any, of chromatic adaptation on hue matching of purple painted samples of different saturations. Five experienced observers were adapted for 1 min to a red field, then asked to find the hue match for each of three test samples from among a set of samples representing the complete hue circuit in 100 steps at middle saturation. The three test samples were of slightly greater saturation and representative of a range of purple samples. The entire procedure was repeated with blue and neutral pre-adapting fields, all under source C illumination. Results indicated that pre-adaptation did influence the hue-match selections, the average red–blue adaptive shift being about one Munsell hue step. Observers made systematically different hue matches for the same test sample, in accordance with their ages. A method for determining graphically the state of adaptation at the time when the hue judgments were made showed that the chromaticity of the test samples was at least as influential as either the neutral surround used or the pre-adaptation stimuli.

Comparison of Munsell and MacAdam Color Spaces

Because of the growing interest in uniform chromaticity scales, a comparison between the Munsell color space and a color space based on MacAdam’s visual sensitivity data is of importance. In order to make this comparison we established the CIE coordinates for a Munsell type cylindrical space sampling conforming to MacAdam’s data. In the color space so formed, a color difference of one-chroma step, for example, will be the same in any region when that difference is calculated from MacAdam’s data. This “MacAdam space” differs materially from Munsell renotation space. The distance of the constant chroma loci from neutral in the purple-blue region is approximately doubled, and the constant hue loci are shifted as much as 10 hue steps in the green and red regions.

Prediction of the Color of Dye Mixtures on Textiles

The relationship between the ratio K/S and reflectance as derived by Kubelka and Munk has frequently been used for analytical work, but little attempt has been made to evaluate the accuracy of its application in calorimetric terms. This evaluation has now been made for dyeings by comparing the predicted color with that actually obtained in textile dyeings, and the difference has been expressed in terms of Munsell notation. In this manner the accuracy of the method has been examined for acid, chromed, and metalized dyestuffs on wool, for “acetate” dyes, and for direct and vat dyes on cotton. We find the accuracy of color prediction for acid dyestuffs on wool to average ±0.5 hue step ±0.1 value step, and ±0.4 chroma step. Predictions for the other applications are nearly as accurate except in those cases where interaction of dyestuff molecules occurs.

A Munsell Color Book in Textiles

A collection of more than one thousand samples of dyed wool flannel has been arranged according to the OSA renotations of the Munsell colors. The choice of sample spacing is the same as that of the Munsell Book of Color, consisting of the even chroma steps at values one to eight for forty hues. The samples were measured by means of the Hardy Recording Spectrophotometer and the Automatic Tristimulus Integrator. Trichromatic data were converted to Munsell renotation by means of the charts prepared for the OSA. Tolerances of 0.15 in value, 0.35 in chroma, and 1.0 hue step at 2 chroma, 0.8 at 4 chroma, and 0.5 at higher chroma were allowed. Because of the brightness of the dyes used, many samples having higher chromas than those of the Munsell Book were obtained. There are more samples in low values, though fewer in high values, than in this painted series of papers. Twelve acid dyestuffs chosen primarily for their light-fastness, brightness, and level dyeing properties were selected for dyeing the wool.