In the Picture Effects palette, each effect that you can make a custom adjustment on provides a Preview option.
You can accelerate performance by unchecking Preview while dragging on the sliders, and then checking it afterwards.
For example, adjusting the five sliders in the Levels effect with Preview checked refreshes the preview five times instead of just once.
Jay Nelson is the editorial director of PlanetQuark.com, and the editor and publisher of Design Tools Monthly. He’s also the author of the QuarkXPress 8 and QuarkXPress 7 training titles at Lynda.com, as well as the training videos Quark includes in the box with QuarkXPress 7 . In addition, Jay writes regularly for Macworld and Photoshop User magazines and speaks at industry events.