Ricoh B079, Service Manual

Page: 371 / 948

Detailed
Des
cription
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IMAGE PROCESSING
SM 6-39 B079/B082
Photo Mode Smoothing for Dithering
Strengthening this SP4903 37 (Smoothing Filter in Photo Mode) makes images
smoother and reduces the occurrence of moiré but can also cause fading.
Strengthen this setting only when necessary. Only valid if SP 4901 001 is at 0.
Smoothing Coefficient Range
SP4903 37 (Smoothing Filter in Photo Mode) 0 ~ 7
Photo Mode Grayscale
This SP mode adjustment sets how grayscales are processed when the user
selects Photo mode on the operation panel.
SP4904 1 Grayscale Photo Mode
Setting Description
0 Dithering and smoothing
1 Error diffusion, MTF filter correction for edges
If “0” is selected, the image grayscales are processed with dithering and filter
processing, just as they are processed with the “Print Photo” selection on the
operation panel. In this case the filter processing means smoothing only. The filter
coefficient for smoothing can be adjusted with SP4904 37 (Smoothing Filter in
Photo Mode).
If “1” is selected, then the image grayscales are processed with error diffusion
processing, just as they are processed with the “Normal” and “Glossy Photo”
settings on the operation panel. The MTF filter applied is the same as that applied
for the “Normal” setting.
To achieve better photo image quality with slightly less clarity in lines and text,
select “0” for dithering. You can also adjust SP4904 2 to achieve better
reproduction of photographs.
On the other hand, to achieve better clarity in text and lines, with a slight sacrifice
in the quality grayscale and smoothness in photographs, select “1” for error
diffusion. To improve the clarity of fine lines and text, you can also increase the
strength of the MTF filter. However, increasing the strength of the filter can also
increase the incidence of moiré in areas of newspaper, magazine, or other
photographs created with dot screening.