View > Gamut Warning
Ctrl/Cmd Shft Y
6.0, 7.0, CS, CS2
The range of colors a computer monitor can display is known as the gamut and the monitor’s gamut has a different range of colors than an inkjet printer can often output. The Photoshop Gamut Warning feature (View > Gamut Warning) shows when the colors on screen are outside of the printer’s capabilities by coloring the problem areas.
The Gamut Warning’s job is to prevent disappointment when you work in RGB mode. It does so by ...