Specific Hue Research Articles

Influence of Language on Colour Perception: A Simulationist Explanation

“How can perception be altered by language?” is the fundamental question of this article. Indeed, various studies have pointed out the influence of colour-related knowledge on object and colour perception, evoked by linguistic stimuli. Here the relevance of the simulationist approach is assumed in order to explain this influence, where the understanding of colour-related words or sentences involves a process of colour simulation that is supported by a neuronal network partially similar to the network involved in colour perception. Consequently, colour-related knowledge and colour perception can interact through a process of pattern interference. In support of this idea, studies are discussed showing priming effects between colour simulation and colour perception, but two limitations are also raised. Firstly, these works all used between-category colour discrimination tasks that allow the intervention of lexical processes that can also explain priming. Secondly, these works control the congruency link between prime and target at the level of ‘colour category’, and no demonstration is made of an influence at the level of specific hues. Consequently, the simulationist view of language/perception interactions seems an interesting way to thinking but more experimens are needed in order to overcome some limitations.

Evaluation of color traps for monitoring Lygus spp.: Design, placement, height, time of day, and non-target effects

Lygus hesperus and Lygus lineolaris are two of the most economically important plant bugs in North America. Here we present results from field trials that evaluated effective trap characteristics for maximizing Lygus spp. and other herbivorous insect capture, while minimizing beneficial insect capture. The response of lygus bugs, several other key herbivore species and predators to hue (white, clear, black, yellow, orange, blue, purple, green and red) and value (black, white and two neutral grays) was examined in alfalfa over three seasons using traps coated with Pestick adhesive. Lygus spp. exhibited a broad response to trap hue, but showed no response to trap value. Additionally, we showed that time of day, trap height and trap placement influenced the number of Lygus spp. captured. More Lygus spp. were trapped from late afternoon to dusk compared to all other times of the day, and more males than females were captured on sticky traps even though the sexes were at parity in field sweep net samples. In the alfalfa setting, male lygus were more likely to be captured on traps placed 20 cm above the ground; traps placed 50 and 100 cm above the ground caught similar numbers of males and females. The highest number of plant bugs was captured when traps were placed in a cleared area between two alfalfa fields; lower numbers were captured on traps at the edge and in the center of the field. All other herbivores exhibited distinct preferences to trap hue and, in some cases, trap value. Predators were rarely trapped, but did exhibit preferences to trap color (i.e., hue and value) characteristics. The potential of using sticky traps with specific hue and value characteristics to monitor Lygus spp. effectively is discussed.

Tye's missing shade of blue

Pure hues are those that are perceived as not being tinged with any other hue. Pure blue is a blue with no perceived component of green, violet or red. A striking empirical finding is that individuals with normal colour vision disagree about which specific hues are pure. What looks like pure blue to John will look like a greenish blue to Jane. This seems to pose a problem for the common-sense view that colours are properties of physical objects or their surfaces. Tye (2006a) notes that this finding has been used to criticize colour objectivism and representationalist accounts of the phenomenal character of colour experience, and to support projectionist views that hold that ‘colour is something we erroneously project onto the world’ (2006a: 174). Projectionism includes the subjectivist view that colours are internal states or properties of the perceiver. Tye’s broad aim is to offer a scenario that accounts...

Tye?s missing shade of blue

Pure hues are those that are perceived as not being tinged with any other hue. Pure blue is a blue with no perceived component of green, violet or red. A striking empirical finding is that individuals with normal colour vision disagree about which specific hues are pure. What looks like pure blue to John will look like a greenish blue to Jane. This seems to pose a problem for the common-sense view that colours are properties of physical objects or their surfaces. Tye (2006a) notes that this finding has been used to criticize colour objectivism and representationalist accounts of the phenomenal character of colour experience, and to support projectionist views that hold that 'colour is something we erroneously project onto the world' (2006a: 174). Projectionism includes the subjectivist view that colours are internal states or properties of the perceiver. Tye's broad aim is to offer a scenario that accounts for the empirical finding in a way that avoids projectionism, thus preserving colour objectivism in general and in particular the representationalism about colour that Tye favors. The empirical finding leads Tye to pose 'The puzzle of true [i.e. pure] blue' (2006a: title): John and Jane cannot both be right about which specific hue is true blue, because they disagree about the specific hue. They cannot both be wrong, because that would entail projectionism. But since John and Jane are both normal perceivers, it cannot be the case that one of them is right and the other wrong.1 Tye's solution to the puzzle is to propose that true blue is an objective property of physical objects, surfaces or volumes, but that human colour perception is not acute enough to determine which objects, surfaces or volumes actually have this property. In Tye's scenario, it was evolutionary advantageous for humans to distinguish between coarse-grained or deter minable colours such as blue and green, but not similarly advantageous to distinguish the fine-grained differences between determinate hues, such

Visualization of three-way comparisons of omics data

BackgroundDensity plot visualizations (also referred to as heat maps or color maps) are widely used in different fields including large-scale omics studies in biological sciences. However, the current color-codings limit the visualizations to single datasets or pairwise comparisons.ResultsWe propose a color-coding approach for the representation of three-way comparisons. The approach is based on the HSB (hue, saturation, brightness) color model. The three compared values are assigned specific hue values from the circular hue range (e.g. red, green, and blue). The hue value representing the three-way comparison is calculated according to the distribution of three compared values. If two of the values are identical and one is different, the resulting hue is set to the characteristic hue of the differing value. If all three compared values are different, the resulting hue is selected from a color gradient running between the hues of the two most distant values (as measured by the absolute value of their difference) according to the relative position of the third value between the two. The saturation of the color representing the three-way comparison reflects the amplitude (or extent) of the numerical difference between the two most distant values according to a scale of interest. The brightness is set to a maximum value by default but can be used to encode additional information about the three-way comparison.ConclusionWe propose a novel color-coding approach for intuitive visualization of three-way comparisons of omics data.

IDENTIFICATION OF TREATED-COLOR FRESHWATER CULTURED PEARLS

Demand for colored pearls has grown during the last thirty years. Colored pearls are rarer than white ones. Thus treated-color pearls have entered the marketplace and their identification became a challenge for the gemologists. With only the help of visual observation, EDXRF and X-radiography, methods that are used today for pearls identification, it is not always easy to identify them. Previous studies, have established that Raman scattering is useful to detect pigments in cultured freshwater pearls. The present study is based on the measurement of the Raman spectroscopy of 35 natural colored freshwater pearls and 15 treated-color freshwater pearls, covering a wide range of typical colors for this material, with green excitation. All natural- color pearls show the two major Raman resonance features of polacetyenic pigments assigned to C=C stretching-at about 1530(±25) cm'1- and C-C stretching - at about 1130(±10) cm' -, regardless of their specific hue. In this paper it is proposed that the absence of these Raman features prove the artificial origin of pigments in a colored freshwater cultured pearl.

Determination by Raman scattering of the nature of pigments in cultured freshwater pearls from the mollusk Hyriopsis cumingi

AbstractThe nature of pigments in naturally colored pearls is still under discussion. For this study, Raman scattering measurements were obtained for 30 untreated freshwater cultured pearls from the mollusk Hyriopsis cumingi covering their typical range of colors. The originality of this work is that seven different excitation wavelengths (1064 nm, 676.44 nm, 647.14 nm, 514.53 nm, 487.98 nm, 457.94 nm, 363.80 nm) are used for the same samples at the highest possible resolution. All colored pearls show the two major Raman features of polyenic compounds assigned to double carbon–carbon (CC) – at about 1500 cm−1 – and single carbon–carbon (CC) – at about 1130 cm−1 – bond stretching mode, regardless of their specific hue. These peaks are not detected in the corresponding white pearls, and therefore seem directly related to the major cause of body color. Additionally, the exact position of CC stretching vibration shows that these compounds are not members of the carotenoid family. Moreover, some changes are observed in intensities, shape and positions of the two main characteristic polyenic peaks from one sample to the next. Similar changes are observed also using several excitation wavelengths for the same point of the same pearl. The exact position of CC stretching vibration of polyenic molecules depends strongly on the number of double bonds (N) contained in their polyenic chain. Hence, using a constrained decomposition of this band for different excitation wavelengths, up to nine different pigments may be detected in the same pearl. Their general chemical formula is R‐(CHCH)N‐R′ with N = 6–14. All our colored samples contained at least four pigments (N = 8–11). Different colors are explained by different mixtures, not by a simple change of pigment. The chemical nature of the chain ends is still unknown, because it cannot be detected with Raman scattering. However, it is possible that these polyenes are complexed with carbonate molecules of the nacre. Similar coloration mechanisms are found in products from other living organisms (e.g. parrots feathers). Moreover, it seems that a similar series of pigments is found in other pearls also, as well as in some marine animals living in similar environments (e.g. corals). Copyright © 2006 John Wiley & Sons, Ltd.

The nature of the chalcogen colour centres in ultramarine-type solids

Blue minerals and gems have always been subjects of fascination to man. In particular lapislazuli is and was highly esteemed and also used as a precious stone and as a pigment. The host compound is the zeolite-type sodalite and the colour centres are S2– and S3–, whose amount ratio determines the specific hue, varying from violet blue to blue to green. But Se2– can also be substituted into the sodalite cages in high percentages, giving the pigment a brilliant red colour. It is even possible to incorporate the rather voluminous radical species Te2 and Te2– into the sodalite matrix. Because the otherwise unstable colour centres are completely screened from the atmosphere and isolated from each other in the cages, they can be fully characterised by various spectroscopic techniques.

Assessing wound severity with color and infrared imaging of reactive hyperemia

This study examined the use of cutaneous reactive hyperemia as a means for noninvasive assessment of wound severity of newly formed temperature-modulated pressure injuries in a porcine model. Two methods to quantify the extent of the reactive hyperemic reflex were developed. First, color image analysis was used to measure the hue of injured tissue. The specific hue of the skin surface of the wounded site was found to provide an indication of the severity of the wounds. Second, infrared imaging, coupled with computer image processing, was used to detect differences in skin temperature. The relative surface temperature of the wounds showed a strong correlation with the presence or absence of deep tissue injury. Both techniques correlated with the severity of the injuries as determined by a histologic assessment of biopsied tissue, but infrared imaging provided the better means to assess wound depth.

Neuronal mechanisms of color categorization in areas V1, V2 and V4 of macaque monkey visual cortex

A landmark study conducted by Berlin and Kay ( Basic Color Terms, University of California Press, Berkeley, 1969, pp. 1–12) demonstrates that well-developed languages contain exactly 11 basic color terms. The basic colors (8 chromatic and 3 achromatic) are situated in specific locations of color space, suggesting a fixed relationship between specific hue and luminance. To determine the physiologic origins of the basic colors, we have studied the responses of cells in visual cortical areas V1, V2 and V4 of the behaving macaque monkey, using chromatic and achromatic stimuli of varying luminance. A total of 569 cells (291 from V1, 205 from V2, 73 from V4) were obtained, and classified as ‘B’ (bright; 43–50% of the total cells in each area), ‘D’ (dark; 6–12% of the total), and ‘ B D ’ (bright/dark; 27–28% of the total) color or non-color cells according to each cell's color/luminance preference in relation to the neutral gray background. About two thirds of ‘B’ cells in each area were color specific, whereas the proportion of color cells in ‘ B D ’ and ‘D’ categories was lower. In all three areas (V1, V2, V4), color cells with preferences for midspectral colors (such as yellow, lime and green) also preferred high luminance levels, while color cells with preferences for endspectral colors (such as red and blue) responded preferentially to luminance levels closer to background. The data provide evidence for categorical color perception within the visual system, as well as providing a physiological basis for the increased saliency of endspectral contours observed at equiluminance in psychophysical studies.

A novel principle for quantitation of fast intracellular calcium changes using Fura-2 and a modified image processing system — applications in studies of neutrophil motility and phagocytosis

A new principle is described for imaging intracellular free calcium [Ca 2+] i changes in single, living cells utilizing the fluorescent probe Fura-2. It is based upon video color mixing in real time and allows high-speed visualization, at maximum image resolution, of [Ca 2+] i changes without digital image ratioing. The epifluorescence images produced by 340 and 380 nm excitations are stored in two memory buffers of a personal computer-based image processing system. Two video signals are generated independently from each buffer and connected to the red and green inputs of a video display. An image is this way created, in which [Ca 2+] i shows up as a specific hue, whereas changes in dye concentration, light intensity, cell thickness show up as variations in brightness of the imaged cells. The method has advantages over conventional ratio imaging, notably simplicity and speed, since no calculations are made. Yet it can be combined with traditional digital image processing. The imaging technique allows monitoring of [Ca 2+] i changes in rapidly moving cells, like neutrophils. It is demonstrated that during random locomotion on serum-coated glass surfaces, [Ca 2+] i levels appeared to oscillate and that the frequency of the oscillations are related to locomotive activity. Furthermore, in Ca 2+ free medium, the cells continue to move and phagocytose in the presence of Ca 2+ ionophore (ionomycin) and 2 mM EGTA. In the presence of 1 mM extracellular Ca 2+, ionomycin-treated cells were not able to move or phagocytose.

CHOROPLETH MAPS ON HIGH RESOLUTION CRTs / THE EFFECTS OF NUMBER OF CLASSES AND HUE ON COMMUNICATION

The research reported here was designed to determine how quickly and accurately map readers viewing choropleth maps on a high-resolution computer monitor are able to identify to which class an areal unit on the map belongs, when the map has between four and eight classes and is produced in shades of either gray, green or magenta. As expected, accuracy rates decreased and reaction times increased as the number of classes on the map increased. Accuracy rates ranged from 91.9% for four-class maps to 68.2% for eight-class maps (averaged for all three colors used in the study). Hue also affected accuracy rates and reaction times, the best results being obtained with achromatic (gray-shaded) maps: 84.5% correct, averaged over all numbers of classes. Maps shaded with magenta proved to be the least satisfactory with an accuracy rate of 72.8%. The study provides cartographers with empirical guidelines regarding what level of map-reading accuracy might be expected for choropleth maps designed with a given number of map classes, in a specific hue, and displayed on a high-resolution graphics monitor.

Preferences for wavelength and intensity in rhesus monkeys: fact or artifact?

10 adult male rhesus monkeys were tested to determine whether systematic preferences existed for specific color or brightness of visual stimuli. In contrast with previous reports no significant preferences for either specific hues or brightness levels were found. Perhaps methodological or subject variables may be responsible for preferential responding in other situations and account for the present inability to confirm prior work on preferences for color and brightness.

Chromatic strength of colors. 3. Chromatic surrounds and discussion.

The relative luminance of a color at the threshold between gray content and apparent fluorescence (fluorence) is not much affected by the luminance of the surround but is greatly affected by its chromaticity. The results indicate that the continuum of color perceptions of a color stimulus seen against a variety of backgrounds is four dimensional. A new concept, “specific hue brilliance,” is shown to describe both the relationship of gray content to the purity of a color of a given dominant wavelength and the appearance of high-purity colors at constant luminance.