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From: SofPasuk@imagen.UUCP
Newsgroups: net.text
Subject: Re: Difference (among engines) -> fonts too thin
Message-ID: <421@imagen.UUCP>
Date: Mon, 23-Jun-86 11:16:08 EDT
Article-I.D.: imagen.421
Posted: Mon Jun 23 11:16:08 1986
Date-Received: Wed, 25-Jun-86 07:07:32 EDT
References: <756@imag.UUCP> <429@opus.nbires.UUCP>
Organization: Imagen Corp., Santa Clara, CA
Lines: 46

> In reference to problems with fonts looking different on different types of
> printers:
> > 
> > I have heard that it is normal. A font printed in a Canon-type printer
> > is really bolder than the same on a Xerox-type.
> 
> We have observed comparable differences on a Canon engine vs a Ricoh
> engine.  I'm told that these two printers differ in one being "write
> black", the other "write white," and that this makes the difference in the
> appearance of fonts.  I know some of the very basics, such as that the
> "resolution" (spacing of pixels) is different from "spot size", and that
> the way the toner fuses affects some things, but I'd really appreciate
> someone who understands the technology posting a little explanation.
> 
> > So, I am looking for people who have the same problem and the "method" for
> > solving it. Is there a special distribution of 300 pixel/inch fonts for
> > Xerox-type printers, or programs to enbold standard TeX 300 pixel/inch fonts ?
> > And what about Troff fonts ?
> 
> Seems that the solution lies in going back to however the bitmaps for the
> fonts are generated and regenerating them with modified algorithms.  In
> what we were doing, the lighter printer tended to allow lines to break up
> where a stroke was one pixel wide for a distance of more than two pixels or
> so.  When strokes break like this, it's more than just a little annoying or
> a little "too light"--it actually gets distracting and hard to read.

This problem is very real!  At IMAGEN, we try to solve the problems in two
ways:

(1)	For fonts, we have Type I fonts for Canon (write black) engines, and
	Type II fonts for Ricoh and Xerox (write white) engines.  The Type II
	fonts are emboldened by at least one pixel for most glyphs smaller than
	14 pt.

(2)	Our Image Processor software automatically "widens" 1 and 2 pixel wide
	vectors when producing images for the write white engines, thus
	preventing "disappearance" of vectors that would be visible on 
	write black engines.

Note that textures are a real problem.  They cannot be artificially "souped-up"
for write white engines and retain their original spacing and visual
characteristics.

Also note that the Ricoh engines' write white problems are less severe than
those of Xerox.  Xerox engines must be VERY CAREFULLY TUNED.  We have seen
some cases of horizontal and vertical pixel widths differing due to mistuning!