Color appearance phenomena

thumb|Pleochroism of cordierite shown by rotating a polarizing filter on the lens of the camera thumb|Pleochroism of tourmaline shown by rotating a polarizing filter on the lens of the camera

Tendency for the peak luminance sensitivity of the human eye to shift toward the blue end of the color spectrum at low illumination levels

of colors: having a sheen, as of metals

perceived hue shift when white light is added to a monochromatic light source

human visual system’s ability to adjust to changes in illumination in order to preserve the appearance of object colors

Dichromatism (or polychromatism) is a phenomenon where a material or solution's hue is dependent on both the concentration of the absorbing substance and the depth or thickness of the medium traversed. In most substances which are not dichromatic, only the brightness and saturation of the colour depend on their concentration and layer thickness.

natural color of an object unmodified by adding light and shadow or any other distortion; best seen on a matte surface, due to it not being reflected, and therefore distorted