QMS 860, User Manual, Page: 192 / 398

NOTE: These gamma correction charts were not generated by the
Administration / Special Pages / Gamma Correction
selection. They are simulated output.
You can test gamma correction using the setgray PostScript
operator. The QMS Crown Technical Reference Manual, which is
an optional purchase available from your QMS vendor, contains
information on setgray.
NOTE: You may want to use the settransfer PostScript operator
to set gamma correction values not predefined in the
printer. (See the QMS Crown Technical Reference
Manual, which is an optional purchase available from
you QMS vendor, for more information on settransfer.)
Gamma Correction Application
You can use gamma correction to correct gray-scale problems for
scanned images or to accentuate detail. An increase in the gamma
value lightens the image. This change does not affect black or white
text, but may affect gray text. Here are some examples:
■ For a photo with a wide range of gray areas from white to
black, you might want to use gamma correction 1.
■ For a photo with very dark or very light areas and few
intermediate gray areas, you might want to use gamma
correction 3.
The main benefit of gamma correction is that it improves the copy
quality of a scanned image.
♦
Chapter 6
P r i n t Q u a l i t y 6 - 7