Luminance–brightness comparisons of separated circular stimuli

Abstract

An experiment was conducted in which observers adjusted the luminance of a 2856-K white comparison source to appear as bright as a chromatic source of known luminance. Twenty different chromatic sources were used, each subtending a visual angle of 1 degree. The results show that, for sources having the same dominant wavelength, the amount of white light required to make a brightness match increases as saturation increases. Additional observations were made using four of the chromatic sources at viewing subtenses of 20' and 6'. These results show that the amount of white light required to make a brightness match decreased as the source size decreased. The rate of decrease was most rapid for the red source.

High visibility safety apparel and nighttime conspicuity of pedestrians in work zones

“…whereas the effect is stronger with larger stimuli (Booker, 1981). In addition, there is evidence that the Helmholtz-Kohlrausch effect diminishes when the ambient illumination is low (Ikeda & Ashizawa, 1991;Stalmeier & de Weert, 1994;Schumann et al, 1996;1998, 1999).…”

Color quality scale

“…Increases in saturation yield better visual clarity and enhance perceived brightness. 7,8 A couple of computational examples from white LED simulations 3 illustrate the deficiencies and limitations of the CRI. First, consider an RGB LED with peaks at 466, 538, and 603 nm.…”

Chromatic variations suppress suprathreshold brightness variations

“…One type of study has considered how the color of a light determines its brightness and whether the brightnesses of different colored lights linearly add when combined (e.g., Booker, 1981;Burns, Smith, Pokorny, & Elsner, 1982;Kaiser & Wyszecki, 1978). These studies have shown that saturated lights tend to appear brighter than equiluminant white lights and that the brightnesses of different colored lights tend not to add linearly when combined.…”