Gamma Correction - Simple Monitor Tests

Simple Monitor Tests

To see whether one's computer monitor is properly hardware adjusted and can display shadow detail in sRGB images properly, they should see the left half of the circle in the large black square very faintly (or not at all), but the right half should be clearly visible. If not, one can adjust their monitor's contrast and/or brightness setting. This alters the monitor's perceived gamma. The image is best viewed against a black background.

This procedure is not suitable for calibrating or print-proofing a monitor. It can be useful for making a monitor display sRGB images approximately correctly, on systems in which profiles are not used (for example, the Firefox browser prior to version 3.0 and many others) or in systems that assume untagged source images are in the sRGB colorspace.

On some operating systems running the X Window System, one can change gamma-correction settings by issuing the command xgamma -gamma 2.1 for setting gamma value to 2.1, and xgamma for querying current value. In Macintosh systems, the gamma and other related screen calibrations are made through the OS control panel. Microsoft Windows versions before Windows Vista lack a first-party developed calibration tool.

In the test pattern to the right, the linear intensity of each solid bar is the average of the linear intensities in the surrounding striped dither; therefore, ideally, the solid squares and the dithers should appear equally bright in a properly adjusted sRGB system.