RGB color model

The RGB color model (UK spelling: RGB colour model) is an additive color model^[1] in which the red, green and blue primary colors of 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.^[2]

"RGB" redirects here. For other uses, see RGB (disambiguation).

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 and colored lighting. 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 red, green, and blue 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.^[3]^[4]

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, OLED, quantum dots, etc.), computer and mobile phone displays, video projectors, multicolor LED displays and large screens such as the Jumbotron. Color printers, on the other hand, are not RGB devices, but subtractive color devices typically using the CMYK color model.

From 0 to 1, with any fractional value in between. This representation is used in theoretical analyses, and in systems that use representations.

floating point

Each color component value can also be written as a , from 0% to 100%.

percentage

In computers, the component values are often stored as numbers in the range 0 to 255, the range that a single 8-bit byte can offer. These are often represented as either decimal or hexadecimal numbers.

unsigned integer

High-end digital image equipment are often able to deal with larger integer ranges for each primary color, such as 0..1023 (10 bits), 0..65535 (16 bits) or even larger, by extending the 24-bits (three 8-bit values) to , 48-bit, or 64-bit units (more or less independent from the particular computer's word size).

32-bit

RGB model and luminance–chrominance formats relationship[edit]

All luminance–chrominance formats used in the different TV and video standards such as YIQ for NTSC, YUV for PAL, YD_BD_R for SECAM, and YP_BP_R for component video use color difference signals, by which RGB color images can be encoded for broadcasting/recording and later decoded into RGB again to display them. These intermediate formats were needed for compatibility with pre-existent black-and-white TV formats. Also, those color difference signals need lower data bandwidth compared to full RGB signals.

Similarly, current high-efficiency digital color image data compression schemes such as JPEG and MPEG store RGB color internally in YC_BC_R format, a digital luminance–chrominance format based on YP_BP_R. The use of YC_BC_R also allows computers to perform lossy subsampling with the chrominance channels (typically to 4:2:2 or 4:1:1 ratios), which reduces the resultant file size.