Compositing tools allow you to make a myriad of adjustments to the color of the images you are working with.
PIGMENT - Priamry colors are Red, Yellow, Blue.
LIGHT - Primary colors are Red, Green, Blue
Computers, Televisions, and Film all use LIGHT to form a picture, so the primary colors we deal with in digital compositing are RED, GREEN, and BLUE, or RGB.
Read about COLOR: http://www.rgbworld.com/color.html
Other values we use to adjust colors:
Hue: how red/green/blue - the shade of the color
Saturation: how saturated/greyscale - how much color
Value: how light/dark - the brightness of the color
Gamma: Gamma correction controls the overall brightness of an image. Images which are not properly corrected can look either bleached out, or too dark. Trying to reproduce colors accurately also requires some knowledge of gamma. Varying the amount of gamma correction changes not only the brightness, but also the ratios of red to green to blue. More on Gamma: http://www.cgsd.com/papers/gamma_intro.html
Alpha: In addition to RG and B each image may or may not have an Alpha channel. An alpha channel is a map of the image's transparency - white is opaque, black is transparent, and greys are verying degrees of opacity.
Filters are effects added to the image in digital image manipulation; A filter effect consists of a series of graphics operations that are applied to a given source graphic to produce a modified graphical result. The result of the filter effect is rendered to the target device instead of the original source graphic.
More on Filters: http://www.w3.org/TR/SVG/filters.html
Examples of filters: Blur, Sharpen, Dilate/Erode, Emboss, Edge Detect, Pixellate, Grain, etc. ***Juse Like Filters in PHOTOSHOP!***