Contrast Adaptation and Wide-Gamut Light Sources
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Authors
Ilic, Ivana
Issue Date
2021
Type
Thesis
Language
Keywords
chromatic adaptation , color , contrast adaptation , lighting , wide-gamut LED
Alternative Title
Abstract
Illuminants vary not only in their mean chromaticity, but also in the range of colors they produce. For example, new high-gamut LED illuminants can expand the saturation of reds and greens by ~30% compared to natural illuminants. We examined how the visual system might adapt to the greater color gamut produced by these illuminants. Stimuli were colors shown on a monitor that simulated surfaces (Munsell spectra) illuminated by a broad (Planckian) or narrow (3-primary LED) illuminant with the same color temperature (2724 or 4000 K). Observers adapted to the simulated surfaces under each illuminant, shown either as a random temporal sequence in uniform fields or in random spatial arrangements in Mondrians. Both illuminants induced strong contrast adaptation. However, simultaneous matches between the two illuminants required significantly higher contrast along the reddish-greenish axis for the LED adaptation, consistent with a sensitivity loss induced by adaptation to the higher red-green contrast created by the LED illuminant. These results suggest that commonly available light sources may significantly alter the states of contrast adaptation in the visual system, and this contrast adaptation is important for understanding the perceptual consequences of both short and long-term exposure to wide-gamut illuminants.