Modeling the effects of gamma on the colors displayed on cathode ray tube monitors

• Published in: Journal of electronic imaging 2004-10, Vol.13 (4), p.688-700
• Main Authors: Soltic, Snjezana, Chalmers, Andrew N
• Format: Article
• Language: English
• ISSN: 1017-9909; 1560-229X
• DOI: 10.1117/1.1785159

This work has been motivated by the rapid growth in the use of digital color imaging technology, together with the ever-increasing interchange of images over the internet. Users of these systems frequently have to make assumptions about the viewing conditions under which such images will be used, as well as the properties of the devices on which the images will be displayed. In this work, we focus on the way in which the displayed colors on a cathode ray tube (CRT) monitor are influenced by the gamma of the display. We have used a simple gain-offset-gain-type model of the performance of the CRT, with gain and offset values together with a set of standard assumptions regarding the display primaries and the white point setting, to enable us to simulate the influence of monitor gamma on the colors displayed. Color differences have been computed in the CIELAB color space. A total of 76 numerically defined color samples were used, of which 66 were chromatic samples and ten achromatic. They were subjected to the influence of eight different gamma values. A reference gamma of 2.2 was assumed in making colorimetric comparisons of the displayed colors for the different "test" gammas against the colors displayed under the reference gamma. The comparisons have been expressed as CIELAB color differences, and they show that the color shifts can be significant (up to 3.58 CIELAB units for a single simulated color sample with a gamma "discrepancy" of 0.1, and up to 9.90 CIELAB units when the gamma discrepancy is 0.3). These results are of concern in the context of the "correct" display of color reproductions-for example, in applications where an accurate impression or understanding of the displayed color is important. ©