# Working with channels

Fotografix uses the RGB colour model in which images are formed by mixing three basic colours - red, green and blue - in varying proportions. These three colours give rise to three colour channels, with each channel containing a portion of the image corresponding to that specific colour.

While most of the time you will view the image normally, certain situations call for inspecting/modifying individual channels. The channel selector right below the layers palette allows you to view and modify the image in different channel combinations. The default, RGB, displays the image normally (in all three channels) while the others display either one or two channels at a time. The Mask channel is not a colour channel, but is used in conjunction with layer masks. (for more information, see Using layer masks)