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From: andrewsh@lonex.radc.af.mil (Harold G. Andrews II)
Newsgroups: comp.graphics,comp.periphs.printers,comp.sys.ibm.pc.hardware
Subject: Re: Gray Scale Graphics For HP IIP
Keywords: laser printer gray scale
Message-ID: <1991Mar12.160953.17086@lonex.radc.af.mil>
Date: 12 Mar 91 16:09:53 GMT
References: <7784@drutx.ATT.COM> <1991Mar11.144450.18991@lonex.radc.af.mil> <1991Mar12.021020.18894@mthvax.cs.miami.edu>
Distribution: comp
Organization: RADC
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In article <1991Mar12.021020.18894@mthvax.cs.miami.edu> bsherman@mthvax.cs.miami.edu (Bob Sherman) writes:
>In <1991Mar11.144450.18991@lonex.radc.af.mil> andrewsh@lonex.radc.af.mil (Harold G. Andrews II) writes:
>
>>In article <7784@drutx.ATT.COM> bal@drutx.ATT.COM (LesebergB) writes:
>>> [Looking for ways to do grayscale on an HP IIP]
>
>>[My response.  Gray scale not possible.]
>
>Well, I hate to argue with anyone, however as I type this I am looking at
>a printout of a digitized photograph of a cat that I printed on a HP IIP
>from a program called Paintworks Gold on the Apple II GS, and it has
>16 gray scales in it. The laser driver used for this was Harmonie from
>Vitesse, and it allows you to choose from 1 to 16 gray scales before
>you print.. So if it is done in software or hardware, I do not know, but
>if the bottom line is the finished result, then yes it can be done..
>
>--
>   bsherman@mthvax.cs.miami.edu |                         | MCI MAIL:BSHERMAN

Well, I hate to argue with you, but what you have in front of you is not
gray scale.  You have something using halftones.  There is a difference.
Using halftones, you could get something to look roughly like a newspaper
image.  Laser printers cannot vary the amount of toner deposited at a point
on the page.  What they can do is create the illusion of different shades
of gray by varying different properties of the dot spacing and overlaying
different "screens" on the image.  The software may ask for the number
of grayscales, but all it does is produce a bitmaped overlay to create the
illusion of grayscale.

Have a good day...


-Andy

*******************************************************************************
* Harold G. "Andy" Andrews II, 1Lt, USAF  *  "Many the man whose punctuality  *
* andrewsh@lonex.radc.af.mil              *   serves only to warm his chair." *
* Rome Laboratory/IRRE                    *                                   *
* Griffiss AFB, NY 13441-5700             *   - M. Kabrisky                   *
* (315) 330-7788  (AVN Prfx 587)          * (Not an official  USAF viewpoint) *
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