IMAGE PROCESSING24 February, 1999
Gamma (gggg) Correction (Printer Gamma)
K
Fig. 1A259D528.WMFFig. 2
A259D529.WMF
(1) KCMY Gamma
Ideally, the gamma curves for Yellow, Magenta, Cyan, and Black are identical, as
shown in figure 1. However, they are not because electrical components always
vary slightly, resulting in varying gamma curves, as shown in figure 2.
The Auto Color Calibration (ACC) procedure can compensate for any
discrepancies in color reproduction. ACC makes new gamma curves for each color
in each mode (text, photo, Bk text). After ACC, the gamma curve for each color can
be adjusted with service programs (see Replacement and Adjustment, Copy Image
Adjustment)
Using these programs, each gamma curve can be adjusted using 4 different
modes: ID max., High ID, Middle ID, and Low ID, as shown on the following page.
If the previous gamma curve was better, the customer can recall it. Alternatively,
the factory settings can be loaded using SP 5-610-004. In addition, the factory
settings can be overwritten by the current gamma settings using SP5-160-005.
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ACEC
