Kodak 9500 manual Screening/Dithering

Screening/Dithering	Screening (dithering) is a method used to simulate gray levels.
	Screening is expressed in terms of levels, ranging from
	2-level to 64-level, with several levels in between.
	Screening is a process that groups neighboring pixels together
	into a super-pixel. The size of the super pixel is determined by
	the screening level chosen (i.e., when a 64-level screen is
	chosen, the super-pixel contains 64 pixels; the super-pixel is 8
	pixels wide and 8 pixels high). Each pixel within the super-pixel is
	assigned a value; either black or white. It is the ratio of black
	pixels to white pixels within the super-pixel which simulates
	varying gray levels. The smaller the screening level, the smaller
	the super-pixel, resulting in higher resolution; similarly, the higher
	the screening level, the larger the super-pixel, resulting in lower
	resolution.

NOTES:

∙Screening is effective for documents containing only photographic images. Mixed mode/error diffusion is recommended for documents containing both text and photographic images. Screening tends to decrease the quality of scanned text.

∙Do not use the Noise filter with screening.

∙When screening and compression are used together, negative compression (less than 1:1) is more likely to occur.

Refer to Chapter 6, Scanner-unique Commands for a description of the LX/Y/Z command.

E-10 A-61122/A-61124 March 1999