Using gamma correction to improve image quality

It is common for many books about OpenGL and 3D graphics to somewhat neglect the subject of gamma correction. Lighting and shading calculations are performed, and the results are sent directly to the output buffer without modification. However, when we do this, we may produce results that don't quite end up looking the way we might expect they should. This may be due to the fact that computer monitors (both the old CRT and the newer LCD) have a non-linear response to pixel intensity. For example, without gamma correction, a grayscale value of 0.5 will not appear half as bright as a value of 1.0. Instead, it will appear to be darker than it should.

The lower curve in the following graph shows the response curves of a typical monitor (gamma of 2.2). The x axis is the intensity, and the y axis is the perceived intensity. The dashed line represents a linear set of intensities. The upper curve represents gamma correction applied to linear values...