Displays continue to evolve in numbers, specifications and applications, with many of these displays being used to access content via the World Wide Web, on telecommunications networks or using proprietary content services. This paper uses an experimental technique to estimate the “gamma” for displays on the World Wide Web. A lightness partitioning experiment was performed by 404 volunteers on the World Wide Web and the resulting data was analyzed to estimate a relationship between lightness and display values. While there are many uncontrolled variables and sources of uncertainty, robust non-parametric statistical analysis results in very low standard errors. The fitted function has an offset for the black point, but the remainder of the lightness versus display digital count data is well fit with a linear function. Overall the data is well fit with an offset of about −0.04 and a gamma of roughly 2.36.

This article considers the color correction of a 3D projection display installation. The system consists of a pair of projectors of the same model modified by INFITECGmbH such that they can be used for projection of 3D contents. The goal of this color correction is to reduce the difference between the two mo-dified projectors such as the color difference between them does not disturb the user. Two new approaches are proposed and compared with the Infitec expert correction. One is based on an objective colorimetric match, the other on the optimization of a transform considering the color difference between the two signals.

Conventionally, the main design parameters for the color gamut of a display are the area in chromaticity space and peak white. This suits normal-gamut 3-primary display design, but is not sufficient for designing wide gamut displays, especially if the display has more than three primaries. In this paper, we propose using the optimal color stimuli as a target for gamut design and illustrate this for displays with 3 to 6 primaries. Applying the design target to a display with an additional white primary (RGBW) [1] confirms that such a display may both have a wide gamut and high peak brightness, but also shows that saturated colors are more difficult to render. Furthermore, the analysis shows that an RGB display is attractive for color rendering and that a display with double red, green, blue, yellow and cyan primaries (see e.g. [2]) can provide a good balance between efficiency and gamut.

What is the minimum amount of information we must transmit along with greyscale values in order to recover a colour original from a grey image? The problem of colour quantization is one of long standing with, for example, a GIF file consisting of single-byte grey values (appropriately compressed using entropy coding) plus a 256×3 colour lookup table in the file header. That lookup table can be generated in various ways (e.g., the standard median-cut algorithm). Here we take the viewpoint that we can generate greyscale values from an input, coder-side, colour image by traversing colour values in a particular order. In forming a grey value, we seek to replace an entire colour plane, orthogonal to the L* in CIELAB colour space, by its grey value, and then reconstitute colour by visiting the byte-value L* greylevels using a path in 3 dimensions such that the order of colour forms a parametric curve from grey plane to grey plane that traverses a rich sampling of colour space while optimally encompassing the gamut of the input image. In that way, we merely have to transmit the parameters for the curve itself along with the grey values in order to recover an approximation of colour. In particular, here we use a curve such that we need to transmit an additional 13 values only. Moreover we can use n-bit grey values with n < 8 for colour-reduced transmission to mobile devices. We find that we do better than the standard GIF file method in terms of CIELAB error for grey and comparably in recovered colour error, and with much less information transmitted. The method rests on an optimization is which grey is selected from nearby colour planes such that the overall grey error is minimized whilst also minimizing the colour error.

It was suggested [Bala_CIC17] that metamerism could be exploited for watermarking applications by utilizing narrowband LED illuminant spectra for breaking apart metamer colors. It was noticed that, for metameric ink reflectances differing only by the K ink contribution, absolute differences between metamer pairs peaked around a few wavelengths: LEDs with those spectra were then used for displaying the watermarks.Here we investigate the idea of interposing a camera and a display system to make the effects produced more pronounced. We develop an optimization to produce a matrix that best transforms the camera sensors such that color differences between erstwhile metamer pairs are maximized, under the new lights. As well, we consider the problem of optimizing on the lighting itself in addition, leading to even more emphatic breaking apart of metamer pairs and thus more visible watermarks.

All museums engage in preventative conservation to insure the longevity of their collections for future generations. One aspect is lighting where there can be a tradeoff between light damage and color appearance. A second aspect is imaging where excessive light exposure reduces accessibility and where digital surrogates increase collection access and reduce handling by maintaining fragile objects in storage. Color fidelity is a critical quality criterion for both aspects. A color target was formulated for museum applications using the absorption and scattering properties of artist acrylic dispersion paints and retouching paints representative of historical and modern paintings. One component of the target was 12 samples varying systematically in CIELAB hue at the maximum achievable chroma. A Euclidean color-difference space based on CIE94 was used to determine chromatic gamut area as a measure of color preference and clarity while color differences weighting hue were a measure of color distortion. Four grays were formulated with a range of color inconstancy under Illuminant A while matching under D65 and four metameric pairs were formulated to represent examples of restorative inpainting with poor pigment selection with respect to metamerism. These samples were very sensitive to changes in spectral power distribution and spectral sensitivity. The target, at this stage only computational, was tested for museum lighting and imaging applications, the results indicative of superior performance to conventional color targets.

Results from two experiments testing flicker sensitivity are presented. Human sensitivity at different visual angles (35°, 60° and 90°), base-color points (red, green and blue), color attributes (Lightness, Chroma and hue) and frequencies (5Hz, 10Hz, 20Hz, 40Hz and 60Hz) were determined using a detection task and fitting of a psychometric curve. Results demonstrate a large effect of eccentricity on the flicker perception. For chroma and hue flicker the sensitivity decreases with the increasing eccentricity at all frequencies. The results for lightness changes show a more complex frequency dependance, with higher sensitivity at larger visual angles for frequencies lower than 15Hz. Generally, we have higher sensitivity to lightness flicker as compared to Chroma and hue flicker for all eccentricities and all frequencies. Lightness, contrary to chroma and hue, is also independent of the base color point. The second experiment demonstrated that mental load significantly impairs detection of flicker in the periphery. The color model used to create the stimuli was designed for central vision and does not account for the density of cones and rods in the far periphery and their interactions. This explains the visibility of chromatic changes even at 90°. Still, for some base points and directions of change, no flicker was detected at any frequency and amplitude for the largest visual angle.

The future of science is in the hands of our school children and it is becoming increasingly difficult to encourage them to choose the “difficult” science majors when they move on to college. This is despite the expanding needs and opportunities for scientists and the importance of scientific research in solving national and global economic and environmental problems. The opportunities for scientists in imaging and color science are endless. This paper describes an effort to stimulate scientific thinking in students of all ages, introduce them to science in a friendly, practical way, and perhaps inspire a few more to join our field or other areas of science and technology. This effort revolves around a website, <whyiscolor.org>, and printed workbook that aim to answer student questions about color in a way that gently introduces them to the science of color through their natural curiosity.

The purpose of this research was to design and complete psychophysical experiments for scaling lightness and lightness differences for achromatic percepts above and below the lightness of diffuse white (L*=100). Below diffuse white experiments were conducted under reference conditions recommended by CIE for color difference research. Overall a range of CIELAB lightness values from 7 to 183 was investigated. Psychophysical techniques of partition scaling and constant stimuli were applied for scaling lightness perception and differences, respectively. The results indicate that the existing L* and CIEDE2000-weighting functions approximately predict the trends, but don't well fit the visual data. Hence, three optimized functions are proposed, including a lightness function, a lightness-difference weighting function for the wide range, and a lightness-difference weighting function for the range below diffuse white.

The color emotion evoked from the two color combination is investigated by varying the area ratio between those two colors. Four color pairs (Dull Blue(R90B 3050)–Pale Yellow(Y1030), Pale Yellow(Y1030) – Vivid Red(R1080), Dark Grey(N7000) – Dull Blue(R90B 3050), Vivid Red(R1080) – Light Green(G2060)) are chosen for the experiment and displayed on the LCD monitor with 9 different area ratio including single colors. For each color combination patch, eight bipolar color emotion pairs are scaled by 10 observers. The three color-emotion factors: color activity, color weight, and color heat are identified by the factor analysis, showing consistent results with previous researches. Color Activity is consisted of clean-dirty, active-passive, and fresh-stale. Color Weight is consisted of heavy-light, hard-soft and tense-relaxed. Color Heat is consisted of warm-cool and masculine-feminine. The responded emotions are compared between two-color combination patches with different area ratio. The observers show diverse emotions for the two color combinations compared to single color emotions. Also it is found that using two colors together having the same feelings do not necessarily enhance the original feelings. In some cases, color emotion of one color strongly affects the perceived emotions for two-color combination.