More About Color Modes

There are eight different color modes available in Photoshop.

RGB - Most widely used - Has three 8-bit channels (red, green, blue); 16.7 million colors - Is the color space of any electronic display (computers, TVs, cell phones, PDAs) - Is device dependent  colors look different on various devices - What you see is very seldom what someone else sees

CMYK (cyan, magneta, yellow, black) - Is the color mode of paper and press; used by printing presses - When converting from RGB to CMYK, some color saturation is lost (known as out of gamut) - In Photoshop, go to View > Gamut warning to see how conversion will affect the image

Grayscale  1 black, 1 white, and 254 shades of gray

Bitmap  black and white

Indexed  256 colors, small file size, used frequently on web pages

Lab  Device independent; works well for moving images from Mac to PC

Duotone  used to increase tonal depth of grayscale image or convert grays to a sepia tone

Multi-Channel  specialized mode used almost exclusively by the printing industry

If you will be using Photoshop to produce images for a variety of output devices, then it is essential to understand which color mode works best in each situation.