Color models and color spaces – Adobe After Effects CS4 User Manual
Page 287
281
USING AFTER EFFECTS CS4
Color
Last updated 12/21/2009
Histogram showing highlight clipping
Histogram showing shadow clipping
Color models and color spaces
A color model is a way of describing color using numbers so that computers can operate on them. The color model
used within After Effects is the RGB color model, in which each color is described in terms of amounts of red, green,
and blue light added together to make the color. Other color models include CMYK, HSB, YUV, and XYZ.
A color space is a variant of a color model. A color space is distinguished by a gamut (range of colors), a set of primary
colors (primaries), a white point, and a tone response. For example, within the RGB color model are several color spaces,
including—in decreasing order of gamut size—ProPhoto RGB, Adobe RGB, sRGB IEC61966-2.1, and Apple RGB.
Although each of these color spaces defines color using the same three axes (R, G, and B), their gamuts and tone
response curves are different.
Though many devices use red, green, and blue components to record or express color, the components have different
characteristics—for example, blue for one camera is not exactly the same as blue for another camera. Each device that
records or expresses color has its own color space. When an image moves from one device to another, image colors
may look different because each device interprets the RGB values in its own color space.
Color management uses color profiles to convert colors from one color space to another, so colors look the same from
one device to another.
More Help topics
Online resources about color models and color spaces
.
Charles Poynton provides an excellent set of resources on
regarding color spaces, color management, and
other color technology.
RGB, CMYK, HSL, HSB, and YCbCr color models.