Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!chinacat!woody
From: woody@chinacat.Unicom.COM (Woody Baker @ Eagle Signal)
Newsgroups: comp.lang.postscript
Subject: Re: Better fill masks.
Summary: from don:
Message-ID: <1797@chinacat.Unicom.COM>
Date: 15 Jan 91 06:04:10 GMT
References: <10315@jarthur.Claremont.EDU>
Organization: a guest of Unicom Systems Development, Austin
Lines: 35

In article <10315@jarthur.Claremont.EDU>, sellswor@jarthur.Claremont.EDU (Scott Ellsworth) writes:
> 
>   Does anyone know of such a set of routines?  It looks like we are
> getting 32-64 distinct grey levels; I thought a 300 dpi printer could do
> better.

From Don Lancasters Laserwriter corner #18.

screen desity   screen angle
50		0		->37 grays
50		5-10		->39 grays
50		15-20		->42 gray
50 		25-30		->35 grays 

etc. (the list is to large to type in here..)

normal default is

53 45 which provides 33 grays, and really is baaaad.

Here is Don's best gray

106 45 {dup mul exch dup mul add 1.0 exch sub} setscreen

This gives you a 9 level gray.

use 85 35 for reduced reproduction, 75 15 for halftone photos
and 135 25 for india ink wash effects.  (these are relly fine)
135 25 gives you only 6 grays but there are super.

There is a secret gray map program that I'll try to post.  It
is available on the Genie Roundtable.

Cheers
Woody