Colors on A Computer Screen

Color from a computer monitor or a TV screen results from a different process than that due to reflection or transmission by a solid or solution. A monitor or TV screen generates three colors of light (red, green, and blue) and the different colors we see are due to different combinations and intensities of these three primary colors.

Each pixel on a computer screen is composed of three small dots of compounds called phosphors surrounded by a black mask. The phosphors emit light when struck by the electron beams produced by the electron guns at the rear of the tube. The three separate phosphors produce red, green, and blue light, respectively.

A sketch of a pixel showing the red, green and blue color produced by the three phosphors.

Black, White, and Gray: Nothing, All, or Some

When no electrons strike the phosphors of a computer screen the phosphors emit no light and the screen appears black. On a white section of a screen all three phosphors are excited and produce light with about the same relative intensities as in sunlight so the light appears white. Gray parts of the screen have all three phosphors producing light, but at a much lower intensity. A sample color block and a sketch of a pixel from the block is shown below for each of these three colors.

The colors black, white, and gray with a sketch of a pixel from each.

Red, Green and Blue: Pure Colors

Red, green, and blue colors are produced by exciting the respective phosphor.

The colors red, green, and blue with a sketch of a pixel from each.

Cyan, Purple, and Yellow: Combinations of Two Colors

Cyan, purple, and yellow are mixtures of two of the primary colors with equal intensities of each.

The colors cyan (light blue), purple, and yellow with a pixel from each.

Mixtures of Three Colors

Mixtures of two or three primary colors with different intensities give the other colors. The combinations for orange (red with a little green), neon pink (red with a little green and a little blue), and turquoise (blue and green with a little red) are shown below.

The colors orange, neon pink, and turquoise with a pixel from each.