Epson ES-1200C - Manual (Page 81)

You can select from three types of halftoning, as well as enable
or disable the halftoning process itself. When halftoning is
disabled, the tones that the data can represent are determined
by the data format. Halftoning is not available when 3
bits/pixel/color or more are selected as the data format, since
halftoning is not necessary for such data. Halftoning modes B
and C are not available with color line sequence reading.
Your scanner also provides four typical dither patterns for l- or
2-bits/pixel/color data format. With suitable software, you can
define two more dither patterns.
Note:
Usually your scanner software or printing method can the
halftoning. Therefore, you should usually not use or dither
patterns when you scan.
mode A
This is the standard halftoning mode. The image is
converted into a hard tone to produce a distinct image, and
is suitable for most purposes. (1 and 2 bits/pixel/color)
mode
With this mode, the image is converted into a softer tone.
This mode is suited for images which contain large areas of
similar tones. (1 bit/pixel/color)
C
With this mode, the image is represented in a way similar
to the screen commonly used for newspaper photographs.
The gradations of the tones are represented by clusters of
different numbers of dots. (1 bit/pixel/color)
A-10 Appendix