About color mode
A color mode determines the color model used to display and print images.
Common models include HSB (hue, saturation, brightness);
RGB (red, green, blue); ARGB (alpha, red, green, blue) and CMYK (cyan, magenta, yellow, black).
PhotoEdit uses ARGB and RGB mode to work with images.
RGB model
A large percentage of the visible spectrum can be represented by
mixing red, green, and blue (RGB) colored light in various proportions and intensities.
PhotoEdit's RGB mode uses the RGB model, assigning an intensity value to each pixel ranging
from 0 to 255 for each of the RGB components in a color image.
For example, a bright red color might have an R value of 246, a G value of 20, and a B value of 50.
When the values of all three components are equal, the result is a shade of neutral gray.
When the value of all components is 255, the result is pure white; when the value is 0, pure black.
RGB images use three colors, or channels, to reproduce up to 16.7 million colors on-screen;
Each channel is defined by 8 bits.
the three channels translate to 24 (8 * 3) bits of color information per pixel.
The RGB model is used by computer monitors to display colors. This means that when working in
color modes other than RGB, such as ARGB, PhotoEdit uses RGB mode for display on-screen.
ARGB model
The ARGB model has an extera channel called Alpha. The Alpha channel represents transparency of RGB color.
An ARGB file (alpha, red, green, blue) is 32-bit, with the extra 8 bits of alpha providing 256 levels of transparency.