Photoshop alpha channels are masks through which you can apply effects. 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 relaod it when you need it using Load Selection (Select > Load Selection).
This photoshop training course will show you how to use Adobe Photoshop to produce all kinds of graphics by manipulating and composing scanned or drawn images. This photoshop training course teaches you how to use photoshop's powerful layering and masking techniques and a wealth of special effect filters.
This Advanced Adobe Photoshop training course teaches participants the techniques necessary to create, manipulate and edit professional quality images with skill and precision. This Photoshop training course is suitable for designers and photographers who have working experience of Photoshop.