A color-difference-matching experiment was carried out using a computer-interfaced video-display system. Two reference color stimuli (i) and (j), and one test stimulus (i,j) surrounded by a large achromatic or chromatic stimulus were presented on the video screen. An observer was asked to adjust the test stimulus until he perceived it to have a color precisely "half way" between the colors of the given reference stimuli. A satisfactory half-way color was the one that produced perceptually equal color differences between (i) and ( i j ) and ( j ) and ( i j ) and simultaneously made these color differences as small as possible. Although the given color difference between the test stimuli (i) and (j) was generally quite large (100-200 just-perceptible color-difference steps) with the achromatic surround condition, the color-difference matching required to obtain the desired half-way color did not present any serious diflculties to the observer. The uncertainty of the chromaticity point of the half-way color was established by an ellipse of small to moderate size surrounding the mean chromaticity setting. The orientation and shape of the uncertainty ellipse was comparable with the orientation and shape of uncertainty ellipses obtained by other investigators studying color-difference matching involving much smaller color differences. The unexpected and noteworthy result of the present study lies in the location of the chromaticity point of ( i j ) relative to those of (i) and (j) as a function of surround color. The location of ( i j ) depends on the saturation of the surround stimulus but not its hue. Some speculative explanations of the observed results are offered.
Kecentl,y, several methods f o r correcting f o r chromatic uduptation have been proposed by Richter, Bartleson, Naya f ani, and others. Psychometric-chroma coordinates are calculated according to these methods f o r surfuce colors illuniinated by various light sources, and are compared with the results of subjective experiments on color appeurunce. For this purpose some experiments using saturated color illuminunts are included. The nonlinear trun,$brmation proposed by Nuyatani and others applied in C'IELAB space correlates best with the subjective apprarunce of surface colors.
Three attributes of color appearance of sixteen samples illuminated by various light sources were estimated directly by two observers. The results are plotted on a subjective chroma diagram, with which the psychometricchroma diagrams calculated from the CIELUV and CIELAB spaces are compared. The comparison and numerical evaluations show that the CIELAB space is much better than the CIELUV and U* V* W* spaces in simulating surface‐color appearance under various illuminants. Substitution of the CIELAB space for the U* V* W* space used in the CIE method of color‐rendering specification is proposed.
Recently , the performance ofLED light sources has been irnproved significantly , therefore those has been used even for museurn lighting where has very severe color rendering properties . When considering the applicatien of LED light sources to museum lighting , we have a couple of questions, about whether Ra , Ri calculated by CIEIJIS color rendering method can properly evaluate color appearance ofobjects illuminated by LED lighting or not . The new coler rendering valuation method now discussed in CIE is outlined .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.