A Gamma Correction, also known as gamma nonlinearity, gamma encoding or just gamma, refers to a nonlinear (logarithmic) equation that encodes or unravels the intensity of light in still photos or movies. Using gamma mapping, color systems, such as RGB or CMYK, can be made more uniform and smoother across a given plane or photographic surface.
Along with charting color uniformity and consistency, gamma can also catalog color contrast in a numeric form. While gamma correction may describe still photographs, it most often refers to images on computer movie screens.
Some common gamma values are the following:
+ PC images are encoded at 0.45 and decoded at 2.2
+ Mac images are encoded at 0.55 and decoded at 1.8.