Adobe Illustrator CS5 One-on-One

243

WORKING WITH TRANSPARENCY

TRANSPARENCY IS all about creating interactions be-

tween objects. Or put more simply, blending. Select a path, group,

or even an entire layer and then blend it with the ones behind it.

The most basic example of blending is the Opacity value in the

Transparency panel. This option lets you mix a selected object with

the stuff in the background according to a percentage—from 100,

opaque, to 0, transparent. Because I’m a shameless epicure, I draw

the analogy of mixing a yummy beverage. Suppose you have a glass

of chocolate syrup and a glass of milk behind it. If you select the

syrup and set it to an Opacity value of 30 percent, 70 percent of

the milk shows through. Alternatively, you could move the milk in

front of the syrup and set the former to an

Opacity of 70 percent. Either way, you get a

glass of chocolate milk. For a more delicious

mix, reduce the milk’s Opacity to 50 percent.

Not everyone fancies syrupy lactose. And

Opacity is just the first of Illustrator’s many

transparency options. Which is why I offer

the cheerful holiday graphic that is Figure 8-1.

Here we see examples of differing Opacity

values (labeled Normal 100% and Normal

35%) and a few of the most useful blend

modes. Like the Opacity value, blend modes

apply computations. Add x of the active layer

to y of the stuff behind it. But blend modes

employ more elaborate arithmetic likely