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RGB color model - A representation of additive color mixing
The RGB color model is an additive color model in which red, green, and blue
light are added together in various ways to reproduce a broad array of colors.
The name of the model comes from the initials of the three additive primary
colors, red, green, and blue
The main purpose of the RGB color model is for the sensing, representation, and
display of images in electronic systems, such as televisions and computers,
though it has also been used in conventional photography. Before the electronic
age, the RGB color model already had a solid theory behind it, based in human
perception of colors.
RGB is a device-dependent color model: different devices detect or reproduce a
given RGB value differently, since the color elements (such as phosphors or
dyes) and their response to the individual R, G, and B levels vary from
manufacturer to manufacturer, or even in the same device over time. Thus an RGB
value does not define the same color across devices without some kind of color
management.
Typical RGB input devices are color TV and video cameras, image scanners, and
digital cameras. Typical RGB output devices are TV sets of various technologies
(CRT, LCD, plasma, etc.), computer and mobile phone displays, video projectors,
multicolor LED displays, and large screens such as JumboTron. Color printers,
on the other hand, are not RGB devices, but subtractive color devices
(typically CMYK color model).
The RGB color model itself does not define what is meant by red, green, and
blue colorimetrically, and so the results of mixing them are not specified as
absolute, but relative to the primary colors. The choice of primary colors is
related to the physiology of the human eye; good primaries are stimuli that
maximize the difference between the responses of the cone cells of the human
retina to light of different wavelengths, and that thereby make a large color
triangle
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