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luminance contrast

quantity relating to the difference in luminance between two surfaces

Note 1 to entry: Widely accepted definitions include:
C = (L1L2) / L1 with L1> L2 (positive contrast),
C = (L1L2) / L1 with L1 < L2 (negative contrast),
C = (L1L2) / (L1 + L2) with L1 > L2,
where C is the luminance contrast and L1 and L2 are the luminances of the two surfaces.

Note 2 to entry: Although luminance contrast is intended to correlate with brightness contrast, it is possible that it does not do so directly because brightness contrast depends on other factors such as the angular separation, the luminance gradient, and any size difference between the two surfaces.

Publication date: 2020-12
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