Lab mode

In Photoshop, Lab mode (the asterisks are dropped from the name) has a lightness component (L) that can range from 0 to 100. In the color picker, the a component (green-red axis) and the b component (blue-yellow axis) can range from +128 to -128. In the Color palette, the a component and the b component can range from +120 to -120.

You can use Lab mode to work with Photo CD images, edit the luminance and the color values in an image independently, move images between systems, and print to PostScript Level 2 and Level 3 printers. To print Lab images to other color PostScript devices, convert to CMYK first.

Lab color is the intermediate color model Photoshop uses when converting from one color mode to another.