The Bezold–Brücke shift is a change in hue perception as light intensity changes. As intensity increases, spectral colors shift more towards blue (if below 500 nm) or yellow (if above 500 nm). At lower intensities, the red/green axis dominates.
This effect is a problem for simple HSV-style color models, which treat hue and intensity as independent parameters. In contrast, color appearance models try to factor in this effect.