No . 96 - 21 Differences in Apparent Contrast in Yellow and White Light ( Reprint )

Notice Qualified requesters may obtain copies from the Orders will be expedited if placed through the librarian or other person designated to request documents from DTIC. Disclaimer The views, opinions, and/or findings contained in this report are those of the author(s) and should not be construed as an offkial Department of the Army position, policy, or decision, unless so designated by other offkial documentation. Citation of trade names in this report does not constitute an official Department of the Army endorsement or approval of the use of such commercial items. Human use Human subjects participated in these studies after giving their free and informed voluntary consent. The purpose of this study was to investigate suprathreshold contrast perception in white and yellow light. The contrast of black-on-white letters was adjusted to match the perceived contrast of yellow-on-yellow letters presented simultaneously on a video display. At lower contrast (7-15%), the apparent contrast of yellow letters was slightly enhanced compared to black-on-white letters (mean enhancement + 23%), but this effect diminished with increasing contrast. independent of letter size, The slight enhancement in yellow light was and could not be explained by luminance differences between yellow and whit displays. This effect may relate to the subjective improvement often reported when wearing yellow (blue-blocking)lenses.