Poynton's homeGamma FAQ -

Frequently-Asked Questions about Gamma


In video, computer graphics, and image processing, image data is ordinarily encoded nonlinearly with respect to light power. The usual encoding incolves a power function; luminance or tristimulus value produced at the display is approximately equal to code value raised to a power gamma. (Luminance is proportional to light power, and proportional to intensity.) Having a good understanding of the theory and practice of gamma will enable you to get good results when you create, process and display pictures.

The Gamma FAQ is distributed in several formats, listed in the table below. If you would like to view this document in typographic quality, or if you would like to print it, I recommend that you obtain the Acrobat PDF version. You can find information about document formats.

Format (about...)

Gamma FAQ

Acrobat PDF format GammaFAQ.pdf (246889 bytes)
PostScript (job file), GnuZip compressed GammaFAQ.ps.gz (161682 bytes)
PostScript (job file), uncompressed GammaFAQ.ps (295882 bytes)
Hypertext (.html) format, with poor typesetting and low-resolution GIF graphics GammaFAQ.html (26 KB + 15 KB inline 72dpi GIF images)
ASCII text-only format, devoid of all graphics GammaFAQ.txt (26926 bytes)

You may be interested in the companion Frequently-questioned answers about gamma, the GammaFQA.

If you think gamma has a bad reputation, read about The rehabilitation of gamma.

If you're interested in color, consult the ColorFAQ.

You might be interested in my note Gamma Correction on the Apple Macintosh.

See also Robert Berger's note about Monitor Gamma.

Other Color links ...

Charles - Color technology