RGB

RGB (red, green, blue) is a color model used primarily in electronic display devices and digital imaging. It represents colors by specifying intensities of red, green, and blue light. When combined at various intensities, these primaries produce a wide range of colors. In additive color systems, absence of light is black, while full intensity of all three yields white.

In most digital contexts, colors are stored as three numeric channels. A common encoding is 8 bits per channel, yielding 24-bit color and 16,777,216 distinct values. Higher dynamic ranges use 10-, 12-, or 16-bit channels and floating-point representations.

Color spaces define the exact red, green, and blue primaries and the reference white used to interpret the numbers. The most widespread RGB space today is sRGB, with a D65 white point. Other spaces include Adobe RGB, ProPhoto RGB, Rec. 709 for HDTV, and Rec. 2020 for UHDTV. These spaces differ in gamut and are chosen to suit particular workflows or devices.

Gamma and linear light are important in RGB processing. Stored RGB values are often gamma-compressed; color arithmetic is more accurate in linear light, so pipelines commonly convert to linear RGB for processing and back to a target gamma for display.

RGB is used in cameras and scanners to capture color, in computer graphics and image editing, and in display technologies to emit light. It is not device-independent: actual reproductions depend on the display’s primaries, white point, and calibration.