UPDATE: The good folks at lynda.com have replaced the bad old corrupted version of this video with a new one that plays properly. Thanks to everyone who let me know that the old one was messed up!
Masking an image is like poking a hole in the background to reveal the foreground. I use this analogy because A) I’m growing a bit weary of the “white reveals, black conceals” line; B) I’m just coming off a ski vacation in Big Sky, Montana, at the end of which I wiped out on a bunch of rocks at the top of the 11,166-foot Lone Peak (see diagram) and poked a purple-looking hole in my knee; and C) masking is exactly like that, except not so purple.
What does that have to do with this week’s feature, alpha channels? The modest but powerful alpha channel serves as a sort of cozy base camp for the hole-poking mask. That is to say, a single alpha channel lets you create a mask, refine that mask, perfect it, and save it for later use. To learn more, check out my Photoshop CS4 Channels & Masks book published by Deke Press in association with O’Reilly Media. Or play the lynda.com-produced video at the top of the page.
All photographs used in this video come to us from image vendor Fotolia. The clouds photo is image #14267355 from ManInBlack. The curly-haired model (which some of you may remember from Feature #18: Smart Objects) is image #12363549 from Valua Vitaly. For an exclusive dekeOnline deal, click this link.
(For a list of all Photoshop Top 4 videos thus far, click here.)
Photoshop Top 4 is available as a downloadable podcast from iTunes. Click here to subscribe. dekePod subscribers will get the videos automatically.