scholarly journals Surface color matching under uniform vs. non-uniform mesopic light levels

2009 ◽  
Vol 9 (14) ◽  
pp. 61-61
Author(s):  
R. Knight ◽  
E. Knight
Keyword(s):  
Color Matching ◽  
Surface Color ◽  
Light Levels

Change of color appearance due to extremely high light level: corresponding colors under 100 and 3000 cd/m2

2019 ◽  
Vol 2019 (1) ◽  
pp. 320-325 ◽  
Author(s):  
Wenyu Bao ◽  
Minchen Wei
Keyword(s):  
Light Level ◽  
Limited Range ◽  
High Light ◽  
Color Preference ◽  
Color Appearance ◽  
Appearance Model ◽  
Color Matching ◽  
Light Levels ◽  
Appearance Models ◽  
Psychophysical Study

Great efforts have been made to develop color appearance models to predict color appearance of stimuli under various viewing conditions. CIECAM02, the most widely used color appearance model, and many other color appearance models were all developed based on corresponding color datasets, including LUTCHI data. Though the effect of adapting light level on color appearance, which is known as "Hunt Effect", is well known, most of the corresponding color datasets were collected within a limited range of light levels (i.e., below 700 cd/m2), which was much lower than that under daylight. A recent study investigating color preference of an artwork under various light levels from 20 to 15000 lx suggested that the existing color appearance models may not accurately characterize the color appearance of stimuli under extremely high light levels, based on the assumption that the same preference judgements were due to the same color appearance. This article reports a psychophysical study, which was designed to directly collect corresponding colors under two light levels— 100 and 3000 cd/m2 (i.e., ≈ 314 and 9420 lx). Human observers completed haploscopic color matching for four color stimuli (i.e., red, green, blue, and yellow) under the two light levels at 2700 or 6500 K. Though the Hunt Effect was supported by the results, CIECAM02 was found to have large errors under the extremely high light levels, especially when the CCT was low.

scholarly journals The color of night: Surface color categorization by color defective observers under dim illuminations

2008 ◽  
Vol 25 (3) ◽  
pp. 475-480 ◽  
Author(s):  
JOEL POKORNY ◽  
MARGARET LUTZE ◽  
DINGCAI CAO ◽  
ANDREW J. ZELE
Keyword(s):  
Color Vision ◽  
Surface Color ◽  
Low Light ◽  
Light Levels ◽  
Color Categories ◽  
Wide Range ◽  
Basic Color ◽  
Color Vision Deficiencies ◽  
Orange Color ◽  
Color Scales

People with normal trichromatic color vision experience variegated hue percepts under dim illuminations where only rod photoreceptors mediate vision. Here, hue perceptions were determined for persons with congenital color vision deficiencies over a wide range of light levels, including very low light levels where rods alone mediate vision. Deuteranomalous trichromats, deuteranopes and protanopes served as observers. The appearances of 24 paper color samples from the OSA Uniform Color Scales were gauged under successively dimmer illuminations from 10 to 0.0003 Lux (1.0 to −3.5 log Lux). Triads of samples were chosen representing each of eight basic color categories; “red,” “pink,” “orange,” “yellow,” “green,” “blue,” “purple,” and “gray.” Samples within each triad varied in lightness. Observers sorted samples into groups that they could categorize with specific color names. Above −0.5 log Lux, the dichromatic and anomalous trichromatic observers sorted the samples into the original representative color groups, with some exceptions. At light levels where rods alone mediate vision, the color names assigned by the deuteranomalous trichromats were similar to the color names used by color normals; higher scotopic reflectance samples were classified as blue-green-grey and lower reflectance samples as red-orange. Color names reported by the dichromats at the dimmest light levels had extensive overlap in their sample scotopic lightness distributions. Dichromats did not assign scotopic color names based on the sample scotopic lightness, as did deuteranomalous trichromats and colour-normals. We reasoned that the reduction in color gamut that a dichromat experiences at photopic light levels leads to a limited association of rod color perception with objects differing in scotopic reflectance.

scholarly journals The color of night: Surface color perception under dim illuminations

2006 ◽  
Vol 23 (3-4) ◽  
pp. 525-530 ◽  
Author(s):  
JOEL POKORNY ◽  
MARGARET LUTZE ◽  
DINGCAI CAO ◽  
ANDREW J. ZELE
Keyword(s):  
Surface Color ◽  
Low Light ◽  
Light Levels ◽  
Orange Yellow ◽  
Color Categories ◽  
Wide Range ◽  
Basic Color ◽  
Distinct Color ◽  
Lower Reflectance ◽  
Color Scales

Several studies document rudimentary color vision under dim illumination. Here, hue perceptions of paper color samples were determined for a wide range of light levels, including very low light levels where rods alone mediate vision. The appearances of 24 paper color samples from the OSA Uniform Color Scales were gauged under successively dimmer illuminations from 10–0.0003 Lux. Triads of samples were chosen representing each of eight basic color categories; red, pink, orange, yellow, green, blue, purple, and gray. Samples within each triad varied in lightness. Observers sorted samples into groups that they could categorize with specific color names. Above 0.32 Lux, observers sorted the samples into the originally chosen color groups with few exceptions. For 0.1–0.01 Lux, the red and orange samples were usually correctly identified as either red or orange. The remaining samples tended to be grouped into two categories, associated with the scotopic sample reflectance. The lowest reflectance samples were below threshold and were named black. The higher reflectance group was named predominately as green or blue-green (three observers; the fourth observer used blue or achromatic). At the three dimmest levels (≤ 0.0032 Lux) there continued to be conspicuous color percepts. Color categories were reliably assigned based on relative sample scotopic lightness. Of the samples above threshold, those with lower reflectance were classified as red or orange (all observers) and the higher reflectance samples as green or blue-green (three observers) or achromatic or blue (the fourth observer). Rods and L-cones presumably mediated color percepts at the intermediate light levels used in the study. At the three lowest light levels there were distinct color appearances mediated exclusively by rods. We speculate that at these light levels the visual system estimates probable colors based on prior natural experience.

Postharvest color development of strawberries: Influence of maturity, temperature and light

1993 ◽  
Vol 73 (2) ◽  
pp. 541-548 ◽  
Author(s):  
W. Kalt ◽  
R.K. Prange ◽  
P.D. Lidster
Keyword(s):  
Titratable Acidity ◽  
Storage Conditions ◽  
Soluble Solids ◽  
Fragaria Ananassa ◽  
Light Conditions ◽  
Surface Color ◽  
Color Development ◽  
Light Levels ◽  
Anthocyanin Concentration ◽  
Concentration Surface

Strawberries (cv. Blomidon) that were either completely white or red at harvest were stored up to 8 d under various temperature and light conditions to examine the effects of storage conditions on postharvest color development. Strawberries, stored at 5, 10, 20 or 30 °C and at light levels of 0, 100 or 200 μmol m−2 s−1, were sampled for anthocyanin concentration, surface color, total soluble solids, titratable acidity, pH of the berry surface, and berry weight loss after 0, 1, 2, 5 and 8 d of storage. Anthocyanin concentration and surface color increased during storage with greater changes in the white-harvested than red-harvested fruit. Temperature, and to a lesser extent light, affected the rate of strawberry color development during storage. After 8 d, the proportions of the two major strawberry anthocyanins, pelargonidin 3-glucoside and cyanidin 3-glucoside, were different in red-harvested fruit and white fruit that became red during storage, compared to field-ripened fruit at harvest. Key words: Fragaria × ananassa, anthocyanin, storage

Color constancy in natural scenes with and without an explicit illuminant cue

2006 ◽  
Vol 23 (3-4) ◽  
pp. 351-356 ◽  
Author(s):  
KINJIRO AMANO ◽  
DAVID H. FOSTER ◽  
SÉRGIO M.C. NASCIMENTO
Keyword(s):  
High Resolution ◽  
Spectral Properties ◽  
Color Constancy ◽  
Hyperspectral Images ◽  
Natural Scenes ◽  
The Sun ◽  
Color Matching ◽  
Surface Color ◽  
Reliable Effect

Observers can generally make reliable judgments of surface color in natural scenes despite changes in an illuminant that is out of view. This ability has sometimes been attributed to observers' estimating the spectral properties of the illuminant in order to compensate for its effects. To test this hypothesis, two surface-color-matching experiments were performed with images of natural scenes obtained from high-resolution hyperspectral images. In the first experiment, the sky illuminating the scene was directly visible to the observer, and its color was manipulated. In the second experiment, a large gray sphere was introduced into the scene so that its illumination by the sun and sky was also directly visible to the observer, and the color of that illumination was manipulated. Although the degree of color constancy varied across this and other variations of the images, there was no reliable effect of illuminant color. Even when the sky was eliminated from view, color constancy did not worsen. Judging surface color in natural scenes seems to be independent of an explicit illuminant cue.

scholarly journals Presenting surface colors on computer controlled CRT displays

2003 ◽  
Vol 16 (2) ◽  
pp. 177-183
Author(s):  
Krisztian Samu ◽  
Klara Wenzel
Keyword(s):  
Color Space ◽  
Color Matching ◽  
Surface Color ◽  
Spectral Matching ◽  
Measuring Device ◽  
Painted Surface ◽  
Color System ◽  
Device Type ◽  
Computer Controlled ◽  
Color Deficiency

It is well known that CRT displays have limited color presentation capability. In everyday cases the drawback mainly shows up in the DTP field where the color space of displays does not match the printers' color space thus the color presented on the display does not correspond completely to printed color. In the contrary case the aim is to present painted surface color on a computer display. Due to the narrow color space of CRT displays direct matching of colors that fall outside of the display's color space is impossible based on CIE xyY color system. When transferring surface colors to displays there are tasks for which not only color matching, but also spectral matching is vital. In "display as measuring device" type of tasks such as color deficiency diagnosis with painted tests transferred to computers, enabling maximal correspondence of both parameters is important because color deficiency is caused by spectral degeneration of the sensitivity of the eyes.

scholarly journals The Application Research of Geometric Language in Modern Furniture

2020 ◽  
Vol 179 ◽  
pp. 02126
Author(s):  
Anlin Huang ◽  
Jianhua Lyu ◽  
Ming Chen
Keyword(s):  
Material Selection ◽  
Color Matching ◽  
Furniture Design ◽  
Application Research ◽  
Surface Color ◽  
Innovative Design ◽  
Symbolic Modelling ◽  
Point Line ◽  
Design Ideas

From the perspective of modern furniture innovative design, this paper analyzes the application extent of geometric language in modern furniture, and provides new design ideas for modern furniture symbolization. By studying the elements of geometric language, such as point, line, surface, color block, shape, through combination, division, superposition, reconstruction and other methods, a variety of symbolic modelling elements are created. Finally, three principles of product symbolic design are summarized, and at the same time, combined with color matching, material selection, man-machine size, using functions, which could be applied into modern furniture design.

scholarly journals Perfect appearance match between self-luminous and surface colors can be performed with isomeric spectra

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Akari Kagimoto ◽  
Katsunori Okajima
Keyword(s):  
Color Matching ◽  
Surface Color ◽  
Color Science ◽  
Cross Media ◽  
Reflected Light ◽  
Tristimulus Values ◽  
Spectral Distributions ◽  
Different Color ◽  
Essential Problem ◽  
Isomeric Pairs

Abstract Surface color results from a reflected light bounced off a material, such as a paper. By contrast, self-luminous color results directly from an emitting light, such as a Liquid Crystal (LC) display. These are completely different mechanisms, and thus, surface color and self-luminous color cannot be matched even though both have identical tristimulus values. In fact, previous research has reported that metameric color matching fails among diverse media. However, the reason for this failure remains unclear. In the present study, we created isomeric color-matching pairs between self-luminous and surface colors by modulating the spectral distribution of the light for surface colors. Then, we experimentally verified whether such color matching can be performed. The results show that isomeric color matching between self-luminous and surface colors can be performed for all participants. However, metameric color matching fails for most participants, indicating that differences in the spectral distributions rather than the different color-generating mechanisms themselves are the reason for the color matching failure between different devices. We experimentally demonstrated that there is no essential problem in cross-media color matching by generating isomeric pairs. Our results can be considered to be of great significance not only for color science, but also for the color industry.

Dynamic Visual Noise Affects Visual Short-Term Memory for Surface Color, but not Spatial Location

2010 ◽  
Vol 57 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Kevin Dent
Keyword(s):  
Short Term Memory ◽  
Spatial Location ◽  
Visual Noise ◽  
Dynamic Visual Noise ◽  
Short Term ◽  
Surface Color ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
Experimental Tool ◽  
Spatial Locations

In two experiments participants retained a single color or a set of four spatial locations in memory. During a 5 s retention interval participants viewed either flickering dynamic visual noise or a static matrix pattern. In Experiment 1 memory was assessed using a recognition procedure, in which participants indicated if a particular test stimulus matched the memorized stimulus or not. In Experiment 2 participants attempted to either reproduce the locations or they picked the color from a whole range of possibilities. Both experiments revealed effects of dynamic visual noise (DVN) on memory for colors but not for locations. The implications of the results for theories of working memory and the methodological prospects for DVN as an experimental tool are discussed.

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