Photoshop alpha channels are masks through which you can apply effects. You can learn more about alpha channels and other effects on an Adobe Photoshop workshop in Brighton, Sussex.
Save time by using these Photoshop Keyboard Shortcuts.
The alpha channel is an 8-bit channel, which means it has 256 levels of gray from 0 (black) to 255 (white). Like masks the white area is active and the black area is masked and 50% gray allows for 50% exposure.
When you use Photoshop’s selection tools, you can apply a filter, adjustment, or modification to effect the selected part of the image. An alpha channel is merely a selection to expose a part of the image for modification.
What is useful about alpha channels is that they can be saved, modified or combined. If you Save a selection (Select > Save Selection), it is sent to an alpha channel so that you can reload the selection when you need it.
Like masks you can paint onto the alpha channel with any of the tools using white black or grey. Filters work in the alpha channels allowing you to modify the mask (not the image).
When you save a selection, (Select > Save Selection) it will be saved as an alpha channel that you can reload it when you need it using Load Selection (Select > Load Selection).
