LIGHTNESS CONTRAST IN CRT AND PAPER-AND-ILLUMINANT DISPLAYS

The increased use of CRT monitors for displaying and controlling stimu li in studies of surface color poses problems of comparability with da ta obtained with traditional paper-and-illuminant methods. A review of comparable studies using the two methodologies revealed that CRT stud ies tend to report larger contrast effects. To investigate factors tha t may be responsible for this difference, simultaneous lightness contr ast was measured using both CRT and paper-and-illuminant presentations . The spatial distribution of luminance in the whole field of view and the visual angles subtended by the displays were controlled. The CRT presentation yielded contrast effects twice as big as those measured f or a paper surface in a homogeneously illuminated room. However, a pap er display under Gelb Lighting yielded almost exactly the same effect size as that measured in the CRT presentation. These results demonstra te that contrast effects in both modes of presentation are affected by the spatial distribution of luminance beyond the basic experimental s timuli.