Visually Closest Cross-Gamut Matches Between Surface Colors

Vision research, 2007

2010 2nd European Workshop on Visual Information Processing (EUVIP), 2010

One of the basic tenets of conventional applied colorimetry is that the whole population of color normal observers can be represented by a single "standard" observer with reasonable accuracy. The 1964 CIE standard colorimetric observer has indeed served us well in all industrial color imaging applications, until recently. With the proliferation of modern wide-gamut displays with narrow-band primaries, color scientists and engineers face a new challenge. Various recent studies, including those by the current authors, have shown that the color perception on such displays varies significantly among color normal observers. Conventional colorimetry has no means to predict this variation. In this paper, we explore this problem by summarizing the results from an ongoing study, and explain the practical significance of this issue in the context of display applications.

Tekstilec, 2015

Displaying desired colours on the screen via the web is still a crucial part of being successful for artists and photographers. The aim of our research was to compare accuracies and varieties of displayed colours on different devices and variations on the same device. Seven Apple display screens of various devices were analysed (iPad 2, iPad 3, iPad Mini, iPhone 4, iPhone 5, iMac and MacBook Pro) using two diff erent browsers Safari and Chrome. For iMac display profi le iMac, and for MacBook Pro display profi le Colour LCD were used. The colour gamuts shown in CIE 1931 x, y and the CIELAB colour diagram were compared with the standard colour space sRGB. The results show that the appearances of colours on diff erent devices are mostly dependent on screen quality. The appearances of colours are largely infl uenced by the choices of browsers for devices that support colour profi les. In regard to devices with included colour profi les within their displays, it is important to choose a browser that enables colour management to take into account the display colour profi le. In our case, the Safari browser takes into account the specifi c display profi le whilst Chrome does not consider those profi le. However the results also depend on other factors. These results are important for graphics and fashion designers as well as textile technologists, who present their work and products to their potential clients on diff erent devices.

2005

Recently, wide-gamut monitors and printers have begun to appear in the market. However, there are no appropriate tools for evaluating color reproduction in such image output devices. This study describes a method to create the image data for evaluation of the wide-gamut devices. The method expands the gamut of the source image in a manner that a color in the image is mapped into a color with higher chroma, which is restricted within maximum chroma of Standard Object Color Spectra (SOCS) database and Pointers database, and the same hue and lightness, by using a chroma mapping function. The method was applied to sRGB images such as XYZ-SCID images to make the test images for evaluating wide-gamut output devices. In order to find the optimal chroma mapping function, a psychophysical experiment was performed, where the test images made with three types of mapping functions were visually evaluated. Results showed that observers judged the test images expanded with nonlinear functions wer...

LEUKOS, 2017

Although it is a critical component of any measure of color rendition, a standardized set of color samples can seldom perfectly match a real space or a real set of observed objects. This means there will always be some level of mismatch between predicted and observed color shifts. This article explores how the color distortions of three object sets that could be used in experiments compare to the color distortions predicted using the color evaluation samples of IES TM-30-15 (TM-30). The experimental object sets include those from a recent experiment [Royer and colleagues 2016], a set of produce (10 fruits and vegetables), and the X-Rite ColorChecker Classic. This numerical analysis focuses on the range of differences between viewed and characterized color shifts-using the TM-30 Fidelity Index (Rf), the TM-30 Gamut Index (Rg) and an alternative to Rg based on ΔC in CIECAM02-over a set of 344 spectral power distributions. The differences depended on the average chroma and spectral features of the sample set. The substantial range of differences shown for the produce and the ColorChecker means that design criteria for color rendition derived using these sample sets are less reliable. Specifiers should carefully consider how average measures of color rendition are applied to real spaces, and experimenters should carefully select experimental objects to avoid mischaracterizations.

Attention, Perception & Psychophysics, 2009

We have previously shown that color appearance can be specified very reliably by a procedure of direct scaling of hue and saturation . In that procedure, participants use percentage scales to describe their sensations of the four unique hue sensations of red, yellow, green, and blue, as well as apparent saturation. Participants' responses to the same stimuli remain stable over long periods of time, do not depend on training or past experience with psychophysical procedures and magnitude estimation, and are independent of the participants' linguistic backgrounds.

Perception & Psychophysics, 2006

Perception & Psychophysics, 1994

Color Research & Application, 2011

The determination of the long-term memory colours of objects has been the subject of investigation for many years. Colour acceptance boundaries have been determined from the visual assessments of objects under variable illumination or by presenting manipulated images of objects on a calibrated computer display. However, a systematic and quantitative rating of the colour of real objects with respect to memory colour is not available at this moment. In this article, nine familiar real objects with colours distributed around the hue circle were positioned in a specially designed LED illumination box. For each object, approximately hundred real illumination spectra were synthesized in a random order keeping the luminance of the object approximately constant.

The Journal of Photographic Science, 1989