Gamma Test Page
Last Update: 2002 Dec 3 

To measure your display's gamma, you pick the image in which the solid square best blends into the 50% background, that is, when the two shades are the closest. It helps to move back from the monitor and squint or defocus your eyes. Remove your glasses, if you have them. The gamma number is indicated below the corresponding square.

If you have an LCD flat-panel display, the gamma will vary according to the viewing angle. Make sure that you are as close as possible to perpendicular to the panel with respect to the square you're viewing.

For good references about gamma, see: