Some colors in the RGB, HSB, and Lab color models cannot be printed because they are out-of-gamut and have no equivalents in the CMYK model. When you choose a non-printable color in either the Adobe Color Picker or the Color palette, a warning alert triangle appears. A swatch below the triangle displays the closest CMYK equivalent.
Printable colors are determined by the current CMYK working space defined in the Color Settings dialog box.