Alpha Channel


In graphics, a portion of each pixel’s data that is reserved for transparency information. 32-bit graphics systems contain four channels — three 8-bit channels for red, green, and blue (RGB) and one 8-bit alpha channel. The alpha channel is really a mask– it specifies how the pixel’s colors should be merged with another pixel when the two are overlaid, one on top of the other.

Typically, you wouldn’t define the alpha channel on a pixel-by-pixel basis, but rather per object. Different parts of the object would have different levels of transparency depending on how much you wanted the background to show through. This allows you to create rectangular objects that appear as if they are irregular in shape — you define the rectangular edges as transparent so that the background shows through. This is especially important for animation, where the background changes from one frame to the next.

Rendering overlapping objects that include an alpha value is called alpha blending.

Read Also:

  • alpha geek

    Slang term used to describe the one person within your office, business, organization or social group who has the most expertise in technical and computer issues.

  • Alpha Version

    A very early version of a software product that may not contain all of the features that are planned for the final version. Typically, software goes through two stages of testing before it is considered finished. The first stage, called alpha testing, is often performed only by users within the organization developing the software. The […]

  • Alphanumeric

    Describes the combined set of all letters in the alphabet and the numbers 0 through 9. It is useful to group letters and numbers together because many programs treat them identically, and differently from punctuation characters. For example, most operating systems allow you to use any letters or numbers in filenames but prohibit many punctuation […]

  • ambient light

    In digital photography terms, ambient light refers to the natural light in a scene that you are shooting.

  • amperage

    The strength of a current of electricity expressed and measured in amperes.


Disclaimer: Alpha Channel definition / meaning should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. All content on this website is for informational purposes only.