Blending Your Blends

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Your layout looks great. It has awesome photos, the perfect typeface and it is all done and ready to go. But wait a minute. What is with the stair-stepped look in the gradients? The top printing problem with blends is an unwanted stair-stepping effect called banding. Instead of a nice smooth blend, you get visible bands. It can happen to the best of designers, but there are some simple ways to prevent this from happening to you.

Banding applies to anything that has a blend. Although different people call them different things, like gradients, fountains, vignettes or degrades, they are all blends. From transparent to a color or from one to multiple colors, they are all blends. PostScript creates blends by generating a series of different toned bands that give the illusion of blending. The human eye canÕt see bands that are smaller than .03 inches. When PostScript makes bands that are larger than that, the stair-stepping effect appears.

So why doesnÕt PostScript just make sure no band is larger than .03 inches? PostScript is limited to a maximum of 256 tints per ink. Because of this limited level, there is a finite number of steps between one color tone and another.

There are three things you can do to avoid banding in your blends:

¥ Make your blends short. The shorter they are, the smaller the bands have to be.

¥ Make your blends in Photoshop. Use the Add Noise Filter to disguise any potential banding. This is the best way to make big blends. Save them as a TIFF.

¥ Use the full range of tones. By increasing the tonal range, you increase the number of tints available. If your blend is from 10 to 30 percent cyan, it has a much greater chance of banding than one that extends from 0 to 90 percent.

Winter 2000 CONTENTS