Playing with Opacity and Blend Modes in Photoshop

If you want to play around with blend modes and opacity but you’re not ready to commit just yet, make a backup copy of an image (it helps to use an image that contains layers, of course). You can play around without permanently hurting the image. If the results of your activities offend you, you can always choose File-->Revert. And try, try again.

Adjusting Layer Opacity
By far one of the easiest ways to make your image look oh so sophisticated is to have one image ghosted over another (and in full, living color in the color insert). Creating this effect is a snap with the Opacity option in the Layers palette. To adjust the opacity, select your desired layer in the Layers palette. Then either access the slider by clicking the right-pointing arrow or enter a percentage value in the Opacity text box. You can also double-click a layer thumbnail, choose Layer-->Layer Style-->Blending Options, or choose Blending Options from the Layers palette pop-up menu (click the triangle in the upper-right corner to open the menu). All three methods bring up the Layer Style dialog box, where you can enter a value or drag the slider for opacity.

The Opacity setting allows you to mix the active layer with the layers below it in varying percentages from 100% (completely opaque) to 0% (completely transparent). Remember that you can adjust the opacity only on a layer, not a background. That’s because there’s nothing behind the background to mix with. You can also change the Opacity percentage by using keyboard shortcuts. With any tool active, except a painting or editing tool, press a number key. Press 5 for 50 percent, 25 for 25 percent. If you are entering a two-digit value, just be sure you type the numbers quickly or else Photoshop will interpret the numbers as two different values. You get the picture. Note that for the default of 100 percent, you must press 0.

Adjusting the Fill Opacity
In addition to adjusting the regular opacity for a layer, you can also adjust the fill opacity. Fill opacity works a little differently from regular opacity. The regular Opacity setting affects layer styles and blend modes which have been applied to the layer. Fill opacity, however, affects only the pixels or shapes that reside on the layer. It doesn’t affect the styles or blends. The drop shadow and emboss styles in the bottom example show through full strength. To adjust the Fill Opacity setting, select your desired layer in the Layers palette and enter a value in the Fill Opacity text box or drag the popup slider. The other methods for adjusting fill opacity are similar to the regular opacity option.