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Layer Masks - Get used to Them - or
Photoshop Layer Mask Shortcuts - Quick Reference
category: digital photography and image editing
With digital cameras commonly producing 6 to 12 mega-pixel images, adjustment layers with their attendant layer masks are more important than ever. A single layer 6 mega-pixel image in native Photoshop format takes 14 MB of space on your hard drive or removable media. If you duplicate the background layer once to apply a blend mode, you double that size to 28 Mb. A 12 mega-pixel image requires 27 MB to store and 55 MB with a duped background layer. Don't even think about the RAM.
An adjustment layer, on the other hand, with an entire 6 mega-pixel image inverted and used as the layer mask takes only 6 MB of additional hard drive space. Further, an adjustment layer with current settings accepted and no mask uses only a few hundred K of space, and can be used with a blend mode just like a duplicate layer. It's just like Apply Image to darken, lighten, or boost color in a layer, but non-destructive and cheap on space. Adjustment Layers and their Layer Masks are here to stay.
With that said, let's get on to the quick reference.
Layer Mask related shortcuts:
When editing photographic images almost any mask you'll need should come from the image itself. Click on the Channels Palette tab so you can see what you're doing, hold down the Ctrl key, and look at the individual color channels by pressing 1, 2, or 3. You're looking for a channel that shows good detail and contrast with the area that you would like to mask. I find that I see some things that I would otherwise miss, if, when viewing a channel, I invert it by pressing Ctrl+I. Pressing Ctrl+I again will toggle the channel back to normal. When you find what you're looking for, the skyline, a waterfall, or whatever, with good detail and contrast, Ctrl-Click on the channel and convert it to a selection. Now press Ctrl+~ to return to normal view and then return to the layers palette to create the mask.
If you're adding a layer mask to a normal layer, click the layer to make it active, and then click on the layer mask icon at the bottom of the layers palette. The layer mask will pick up the selection outline making selected areas white and the rest black. Shades of gray in the mask will be partially selected.
If you're adding the mask to an adjustment layer, create the layer and the layer mask that comes along with it while the selection is active, as above, and when the dialog box for the adjustment you would like to make comes up, just click OK to accept the current settings and come back to finalize the adjustment after you have edited the mask.
Now, to edit the layer mask Alt-Click on the Layer Mask thumbnail and all Photoshop editing tools are available to edit the mask. As the mask looks increasingly less like the image, very soon if it's inverted, you may want to edit the mask while looking at the image at the same time. To see the mask as a rubylith overlay and toggle in and out of rubylith mode, press the \ (backslash) key. Remember, rubylith mode looks the same on the screen whether your editing the mask or the image, so be careful. If you're editing the layer mask on a normal layer, watch for the paintbrush or the layer mask icon in the active layer to tell you which is active. Adjustment layers can be trickier because they never show the paintbrush, even when the mask is not active; they only show the layer mask icon. When in doubt click the layer mask thumbnail.
Finally, to build a new layer mask using a modified version of an old one, just Ctrl-click on the original mask's thumbnail to convert it to a selection, and then create an adjustment layer while the selection is active. The adjustment layer's mask will pick up the selection for editing. If you want to add a mask to another mask and create a third mask, Ctrl-click on the first, creating a selection, then Shift+Ctrl-click on the second, adding the selections together. Then with the combined selections active, create your target mask, or Adjustment Layer and Mask.
He said on 06.06.05 @ 02:02 PM CST
