RGB stands for red, green, blue. In a TGA or VTF, each pixel of the image is defined by three bytes that define how much red, green, and blue light are added together to produce the color in that pixel. Textures can also have a fourth channel, called alpha, which can store other information for each pixel (usually opacity).
- The three or four separate values for each color are called 'channels'. Shaders in Source can manipulate each channel individually to produce color effects.
- Within materials, an RGB colour is a material vector.