Ciekawostka: A healthy (non-colorblind) human eye can distinguish between 500 shades of gray

Evidence: 41 • authority: 72

In visual physiology, adaptation is the ability of the retina of the eye to adjust to various levels of light. Natural night vision, or scotopic vision, is the ability to see under low-light conditions. In humans, rod cells are exclusively responsible for night vision, as cone cells are only able to function at higher illumination levels. Night vision is of lower quality than day vision because it is limited in resolution and colors cannot be discerned; only shades of gray are seen. In order for humans to transition from day to night vision they must undergo a dark adaptation period of up to two hours in which each eye adjusts from a high to a low luminescence "setting", increasing sensitiv…

Evidence: 31 • authority: 80

The perception of surface gray shades and the computational goals of human vision

Evidence: 31 • authority: 72

Variations of gray or grey include achromatic grayscale shades, which lie exactly between white and black, and nearby colors with low colorfulness. A selection of a number of these various colors is shown below.

Evidence: — • authority: 35