Screen Gamma Test
Gamma is
the non-proportional rate at
which a monitor screen "gets brighter" as the electrical signal applied
to it increases. Increasing gamma value makes the darkest parts of a
picture get brighter faster than the lighter areas. This brings out
shadow detail without burning out the highlights. Most PC-based
image-editing applications assume your monitor has a gamma of 2.2 and
make corrections to the image data as they send it to your screen. If
gamma is being over-corrected for your monitor, the dark areas will be
pale and washed out looking (too light). If gamma is being
under-corrected, the dark areas will look excessively dark; trying to
fix this by turning up the brightness will merely wash out the
highlights.
This
test pattern can reveal the actual monitor gamma. Once you have
determined this, a (very) few monitors and some programs will allow you
to make compensating adjustments. To use the test, blur your eyes or
move far enough away from your monitor so that you can't see the
textured pattern in the background of this image. The square whose
brightness most closely matches the background shows the current gamma
of your monitor.
Note
that on LCD (flat panel) monitors, that the results will be wildly
affected by your viewing angle relative to the screen. For the most
accurate results, your line of sight to the monitor must be absolutely
perpendicular to the monitor surface.
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