Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ulowell!cbmvax!daveb
From: daveb@cbmvax.UUCP (Dave Berezowski)
Newsgroups: comp.sys.amiga
Subject: Re: EpsonX Printer Driver Weirdness
Message-ID: <5380@cbmvax.UUCP>
Date: 30 Nov 88 20:16:36 GMT
References: <6403@netnews.upenn.edu>
Reply-To: daveb@cbmvax.UUCP (Dave Berezowski)
Distribution: na
Organization: Commodore Technology, West Chester, PA
Lines: 36

In article <6403@netnews.upenn.edu> ranjit@eniac.seas.upenn.edu.UUCP (Ranjit Bhatnagar) writes:
>I don't know that I want to call this a bug - perhaps it's just
>a SIDE EFFECT.
>
>If you print the picture "Lady" from the Digipaint distribution
>disk (it's a 320x400 HAM mode monochrome image) as a 3 inch wide
>image, using halftone shading, under the EpsonX driver in 1.3,
>then in densities 3, 5, and 6 (the ones which can not print
>consecutive horizontal dots), her lips vanish.
>
>Really.  All of the picture comes out beautifully except the
>chin is washed out, and the lips vanish.  My best guess is that
>the restriction on horizontal dots causes a severe reduction in
>contrast at the darker gray levels.  Thus making these density
>modes useless for most gray scale dumps as well as for fine detail.
>Oh well.  Someone from Commodore already mentioned that this limitation
>probably won't be fixed in software because it's not Commodore's 
>problem.  Besides, waiting for a six-pass screen dump to finish 
>would cause nervous breakdowns.  
>
>	- Ranjit
>
	You've hit the nail on the head exactly!  The printer device thinks
that the printer has 240 dpi in the x direction and generates all the dots
necessary to draw the picture.  The printer unfortunately drops EVERY SECOND
DOT, thus you see wierd things happen.  That is why it is pointed out in the
V1.3 enhancer manual that the printer cannot print two consecutive dots.
The printer driver tells the printer device that the printer has 240 xdpi
because the printer (as spec'd by the manf.) actually can place dots at
240 xdpi (just not consecutively).  This is a limitation of the hardware
in the printer and (in my opinion) a limitation in the romware inside the
printer.  Some printers (Nec specifically) actually account for this and
automatically do a double pass to print the dots it missed on the first
go round.  Kudos to Nec for putting this kind of smarts in their firmware!

	David Berezowski