The patterns on [these sets] represent an ultimate test of monitor quality and calibration. If your
monitor is functioning properly and calibrated to gamma = 2.2 or 1.8, the corresponding pattern
will appear smooth neutral gray when viewed from a distance. Any waviness, irregularity, or
color banding indicates incorrect monitor calibration or poor performance. You will see
irregularities if the black level (brightness control) is set too low, causing dark areas clip,
if the monitor saturates in bright areas (a sign of old age), or if your monitor is
malfunctioning in any way. The optimum black level setting is typically a little higher than
the lowest level where smoothness can be achieved. This setting should be consistent with the
gamma chart instructions, [in previous chart].


For more information:

http://www.normankoren.com/makingfineprints1A.html#gamad

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