From the course: Photoshop: Channels and Masks

The alpha channel is home to the mask - Photoshop Tutorial

From the course: Photoshop: Channels and Masks

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The alpha channel is home to the mask

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- Now that you know how the color bearing channels work, it's time to introduce you to the non-color-bearing channels, which are known as alpha channels. I explain why they're called alpha channels sin the very next movie, but generally speaking, alpha channels contain masks. Let's imagine a simple scenario. You start with a standard rectangular selection. Were you to convert that selection to an alpha channel, everything inside the rectangle would be white, and everything outside would be black. So, just as everything inside the selection is selected, and everything outside is protected, where an alpha channel is concerned, white means selected, and black means protected. So, whatever modification you apply, whether you're moving, or re-coloring, or applying a special effect, it will only happen to the area represented in white. But it gets better. Masking is not all black-and-white. An alpha channel is a grayscale image, after all. And those grays translate to subtle transitions, soft edges, gradient fades, and so much more than you can do with a standard selection outline. So, here's how it breaks down. An alpha channel contains a mask. Masks and selection outlines are the same thing expressed in different ways. Photoshop sees a mask every time you make a selection. So, an alpha channel lets you store a selection for later use. And it lets you elaborate on that selection, even using the selection tools themselves. This is just a warm-up, an introduction to alpha channels, and a first glimpse into the magic of masking in Photoshop. But you get to create this guy, so get psyched for that.

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