Understanding color models
You need a precise method to define colors. Color models provide various methods to define colors, each model defining colors through the use of specific color components. There are a range of color models to choose from when creating graphics.
CMYK color model
The CMYK color model uses the following components to define color:
The cyan, magenta, yellow, and black components are the amounts of cyan, magenta, yellow, and black ink that a CMYK color contains and are measured in percent from 0 to 100.
The CMYK color model, a subtractive color model, is used to produce printed materials. Subtractive color models use reflected light to display color. When you combine cyan, magenta, yellow, and black, so that the value of each component is 100, the result is black. When the value of each component is 0, the result is pure white.
RGB color model
The RGB color model uses the following components to define color:
The red, green, and blue components are the amounts of red, green, and blue light that an RGB color contains and are measured in values ranging from 0 to 255.
The RGB color model is an additive color model. Additive color models use transmitted light to display color. Monitors use the RGB color model. When you add red light, blue light, and green light together, so that the value of each component is 255, the color white is displayed. When the value of each component is 0, the result is pure black.
HSB color model
The HSB color model uses the following components to define color:
Hue describes the pigment of a color and is measured in degrees from 0 to 359 (for example, 0 degrees is red, 60 degrees yellow, 120 degrees green, 180 degrees cyan, 240 degrees blue, and 300 degrees magenta). Saturation describes the vividness or dullness of a color and is measured in percent from 0 to 100 (the higher the percentage, the more vivid the color). Brightness describes the amount of white that the color contains and is measured in percent from 0 to 100 (the higher the percentage, the brighter the color).
Grayscale color model
The grayscale color model defines color by using only one component, lightness, which is measured in values ranging from 0 to 255. Each grayscale color has equal values of the red, green, and blue components of the RGB color model. Changing a color photo to grayscale creates a black-and-white photo.
For information about changing the color mode of images, see “Changing color modes.”