Wednesday, January 24, 2007
Understanding and using layers increases your tools and capabilities for refined image processing
Women's softball gets short shrift in the media, yet these young athletes play scrappy, entertaining, fast-pitch softball. The UCLA team consistently makes the playoffs for the NCAA World Series of softball, coming in first in 2004 and second in 2005.
Stacks Of Things
The Layers palette in Photoshop is simply a stack of items that's always viewed from top to bottom (everything here also applies to Photoshop Elements, Jasc Paint Shop Pro and other image-editing programs).
What you see on the screen as your image is exactly what you'd see if you looked down on your stack of images. Remove a photo from the stack or turn off that layer from a group of layers, and you see a new group of photos. You'll see the same group in both the real stack and the layered stack, with elements revealed because the photo is missing, not blocking the view of any lower images.
You also could put a piece of clear yellow plastic over the group, and everything under that plastic would look yellow, though, of course, you haven't actually made anything yellow. You can duplicate these effects exactly with Layers.
Layers in your image-processing program, then, is simply a stack of things that are viewed from top to bottom, and each part of that stack can be affected in isolation, just like you could do something to one photo in a pile of photos without affecting the others. Layers can be clear, opaque or any level of opacity in between (opacity is simply the opposite of transparency, but it's the word used by Adobe).
An Adjustment Layer adds a layer of instructions that affects what's below it, but no changes actually are made to the items below. It's like a filter; if you put a red filter on your lens, the world doesn't change to red, but it will photograph as red. If you place a green piece of plastic wrap on a photograph, the photograph isn't green, but it sure looks green in some areas because of the effect of the plastic. This is what Adjustment Layers do.
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