context1: Melanin, a darkly colored pigment, helps the choroid limit uncontrolled reflection within the eye that would potentially result in the <strong>perception</strong> of confusing images. In humans and most other primates, melanin occurs throughout the choroid. In albino humans, frequently melanin is absent and <strong>vision</strong> is low.
context2: Unlike the RGB and CMYK color models, Lab color is designed to approximate human <strong>vision</strong>. It aspires to perceptual uniformity, and its L component closely matches human <strong>perception</strong> of lightness. It can thus be used to make accurate color balance corrections by modifying output curves in the a and b components, or to adjust the lightness contrast using the L component.