Color Models

Color Vision The color-responsive chemicals in the cones are called cone pigments and are very similar to the chemicals in the rods. The retinal portion of the chemical is the same, however the scotopsin is replaced with photopsins. Therefore, the color-responsive pigments are made of retinal and photopsins. There are three kinds of color-sensitive pigments:  Red-sensitive pigment  Green-sensitive pigment  Blue-sensitive pigment Each cone cell has one of these pigments so that it is sensitive to that color. The human eye can sense almost any gradation of color when red, green and blue are mixed. Red, green, and blue phosphor dots from standard television screen.

Additive vs. Subtractive Color

Prism Using a prism, we can see that what we see as “white light” is actually made up of all the colors of the rainbow.

Subtractive Color Subtractive color systems start with white light. Colored inks, paints, or filters between the viewer and the light source or reflective surface subtract wavelengths from the light, giving it color

Subtractive Color The CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected. Such a model is called subtractive because inks “subtract” brightness from white.

CMYK In most color printing, the primary ink colors used are cyan, magenta, and yellow. Cyan is the complement of red, meaning that cyan acts like a filter that absorbs red. The amount of cyan applied to a paper will control how much red will show. Magenta is the complement of green, and yellow the complement of blue. Combinations of different amounts of the three inks can produce a wide range of colors; this is how artwork reproductions are mass-produced, though for various reasons a black ink is usually used as well. This mixture of cyan, magenta, yellow and black is called CMYK.

Additive Color An additive color model involves light emitted directly from a source. The primary colors of additive light: red, green and blue (RGB) are used to create other colors.

Additive Color Combining one additive color with another produces the additive secondary colors: cyan, magenta, and yellow. Combining all three additive colors results in white.

RGB James Clerk Maxwell is credited as being the father of additive color. He photographed a tartan ribbon on black-and-white film three times, first with a red, then green, then blue color filter over the lens. The three black-and- white images were developed and then projected onto a screen with three different projectors, each equipped with the corresponding red, green, or blue color filter used to take its image.

Additive Color The additive color system is used in computer monitors and TVs. If you are designing for a computer screen, choose the RGB Color Model