🚀 go-pugleaf

Re <9210052318.AA27301@cookie-crisp>
<9210051644.AA07993@life.ai.mit.edu>:

> Having recently installed Ghostscript 2.5.2 on our Sun IPC, upgrading from
> version 2.4, I find that the output quality of dithered colour images to 
> our HP Paintjet/DEC LJ250 is vastly inferior to that of the previous release.
> The images are much coarser and there is a pronounced chequerboard effect 
> over large areas of solid colour. Most of the images being printed are shaded
> solid models from CAD systems captured from the Sun colour screen.
> 
> Are other users experiencing this this problem and can anything be altered
> to mimimise these effects?

2.4 used a 16x16 pixel ordered dither on all devices.  This did not
seem appropriate for printers, where single pixels often overlap, so
I changed it to a 45-degree, 45 DPI spot dither.  You can change it
back by finding the line in gs that reads
	dup 150 lt systemdict /DITHERPPI known not and
and changing it to
	true

Halftone screens are an area where I don't have much experience.  I
would appreciate getting in touch with someone experienced who can
help me improve Ghostscript in this area.

L. Peter Deutsch :: Aladdin Enterprises :: P.O. box 60264, Palo Alto, CA 94306
ghost@aladdin.com, ...decwrl!aladdin!ghost ; voice 415-322-0103 ; fax 322-1734
	    "Implementation is the sincerest form of flattery."