RGB

• 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.
• RGB is a device dependent color model, different devices detect or reproduce a given RGB value differently.
• RGB color values are supported in all browsers.
• RGB colors are generally used in web.

Advantages

• RGB files size are 25% smaller than CMYK.
• RGB color range are larger than CMYK.
• Using RGB the images will completely web ready with no color variation.
• Many filters and functions are only available to use in an RGB color mode in Photo Shop and similar programs.

RGB color model theory

Photography

• The first experiments with RGB in early color photography were made in 1861 by Maxwell.
• It involved the process of combining three color-filtered separate takes.
• To reproduce the color photograph, three matching projections over a screen in a dark room were necessary.

Television

• Before the development of practical electronic TV, there were invention on mechanically scanned color systems as early as 1889 in Russia.
• The color TV pioneer John Logie Baird demonstrated the world's first RGB color transmission in 1928, and also the world's first color broadcast in 1938, in London.
• In his experiments, scanning and display were done mechanically by spinning colorized wheels.

Personal computers

• IBM introduced a 16-color scheme (four bits—one bit each for red, green, blue, and intensity) with the Color Graphics Adapter (CGA) for its first IBM PC (1981), later improved with the Enhanced Graphics Adapter (EGA) in 1984.

Numeric representation

• The color is expressed as an RGB triplet, each component of which can vary from zero to a defined maximum value.
• If all the components are at zero the result is black, if all are at maximum, the result is the brightest representable white.
• From 0 to 1, with any fractional value in between. This representation is used in theoretical analyses, and in systems that use floating point representations.
• Each color component value can also be written as a percentage, from 0% to 100%.
• In computers, the component values are often stored as integer 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.
• 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 32-bit, 48-bit, or 64-bit units.