1. Technology
Alpha Channel
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 Related Terms
• mask
• native file format
 
 
Definition: An alpha channel is a special type of channel used in graphics software for saving selections. Most bitmap editing software allows you to save multiple alpha channels with an image when it is saved in the program's native file format. Any of the alpha channels can be reloaded as a selection or mask at any time, even after closing and reopening the image.

A few of the standard image formats (TIFF and PNG, for example) provide support for an embedded alpha channel which represents up to 256 levels of transparency. Images with an embedded alpha channel can be ported to other applications while retaining transparency as long as the other application also supports alpha channels. Like a mask, the darkest areas of an alpha channel is most transparent, white areas are opaque, and shades of gray represent varying levels of transparency.

Also Known As: mask, selection

Elsewhere on the Web:

Anatomy of an Alpha Channel
The technical answer to "What is an alpha channel?" From Thomas Summerall, of Media Lab, Inc.

 


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