Text/Photo Mode - Gestetner B003 Service Manual

Text/Photo Mode

Text/photo mode achieves high quality reproduction of pictures with accurate
grayscaling. Processing is conducted with the special γ coefficient which
reproduces a wide range of grayscale. Compared with the text mode, text
reproduced in the text/photo mode could appear lighter and textured backgrounds
could appear on copies, but the incidence of moiré is reduced by the employment
of a weak MTF filter. Because Photo Priority uses an MTF filter weaker than that of
the Normal setting, the quality of the image is improved with the elimination of
moiré. The Text Priority selection uses an MTF filter stronger than that of the
Normal setting, thus increasing the sharpness of lines.
Image Processing Flow
Scanner Image Shading Correction
Correction
Pre-Entry Background Erase
Processing
Magnification Main Scan Direction
Independent Dot Erase
Filter Processing
Density Control
Grayscale
Processing
SM
Related SP Modes
!
SP4-903-67 (Background Erase Level)
!
Smoothing SP4-903-13 (Pre-Filter Coefficient 25%~64%)
SP4-903-14 (Pre-Filter Coefficient 65%~154%)
!
SP2-909-01 (Main Scan Magnification)
!
SP4-903-62 (Independent Dot Erase Level)
!
MTF Correction SP4-903-39~54 (MTF Filter Coefficients,
Strength)
!
γ Coefficient
!
Error Diffusion SP4-904-07 (Error Diffusion Pattern)
6-23
IMAGE PROCESSING
B003/B004/B006/B007