Painter is a great program but for 4-color process work you can't beat Photoshop. Painter 6 can open psd 4-C tiffs but not if it's seperated into chanels. Painter will save to 4-C process but the output preview isn't too, you can't be sure of your final color. Greens in particular are problomatic. In Photoshop you have much finer control over ink gain, undercolor removeal and gray componant replacement, Painter has none of these.