RYB color model as the "three" psychological primaries, with black and white occasionally added as a fourth and fifth. The cyan, magenta, and yellow primary colors associated with CMYK printing are sometimes known as "process blue", "process red" and "process yellow". RYB color model RYB (an abbreviation of red–yellow–blue) is a historical set of colors used in subtractive color mixing and is one commonly used set of primary colors. It is primarily used in art and design education, particularly painting. RYB predates modern scientific color theory, which has determined that cyan, magenta, and yellow are the best set of three colorants to combine,
Green green pigment in green eyes; like the color of blue eyes, it is an optical illusion; its appearance is caused by the combination of an amber or light brown pigmentation of the stroma, given by a low or moderate concentration of melanin, with the blue tone imparted by the Rayleigh scattering of the reflected light. Green eyes are most common in Northern and Central Europe. They can also be found in Southern Europe, West Asia, Central Asia, and South Asia. In Iceland, 89% of women and 87% of men have either blue or green eye color. A study of Icelandic