Welcome to a block of the most powerful options inside Photoshop: Opacity and Blend Modes. These include the options at the top of the Layers palette, not to mention those associated with the brush tool, the Calculations command, and a whole lot more. What these options do is blend pixels together, entirely parametrically—meaning no harm done—using math. Beautiful, lovely, gorgeous math.

Luckily, the math is trivial. For example, changing the Opacity is like mixing a cocktail with, say, 25% of the active layer and 75% all layers below. The mysterious Fill value drops away a layer without affecting its effects (as documented in Feature #17: Layer Effects). Assigning a blend mode (Normal and the like) is like shining a light or casting a shadow. Screen makes everything brighter and, if that’s not enough, Linear Dodge sets it on fire. Multiply darkens it followed by Linear Burn, which scorches it. Overlay and the others map textures onto each other. In every event, the active layer infuses those behind it with a palpable, tangible, absolutely tactile sense of life.

My job in this video is not to document every one of the 25-plus blend modes. Rather, I show you the most essential ones and provide you with guidance for how to use them. As well as Opacity and Fill, of course. And just for larfs, I wrap up the whole thing with a demonstration of the Knockout option. All in 12 minutes, no less! It goes by fast, so hold onto your socks.

As always, the base photographs hail from image vendor Fotolia. The battling couple is file #3001446 from Ron Chapple Stock. The parchment is file #2278154 from Jumpingsack. For an exclusive dekeOnline deal, click this link.

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