Pale and pastel. To give a pastel-like quality to a photo’s colors, decrease the saturation.
Going gray. If you drag the Saturation slider all the way to the left, you create a grayscale version of the photo. Generally, the B & W option under the Effects tab does a better job, but experiment and see which version you like best.
Note: If the skin-tones box is checked, you can’t completely desaturate the photo. To create a grayscale image, uncheck the box.
Watch your gamut. If you significantly increase a photo’s saturation, you probably won’t be able to print a version that matches what you see on screen. Printers have a much narrower color range, or gamut, than does the Mac’s screen.