laser-lovers@uw-beaver (06/04/85)
From: Christopher A Kent <cak@Purdue.ARPA>
We just got our 1200A hooked up, and our LaserWriter appeared last
week. We don't have TranScript yet, but we have typed in one or two
files from the Cookbook. I ran them off on both, and thought I'd report
on the comparison. The QMS was "professionally" installed, and perhaps
tuned somehow; we just took the LaserWriter out of the box and plugged
it in.
This is the example PostScript code, in case you want to try it:
/unitsquare
{ newpath
0 0 moveto
0 1 lineto
1 1 lineto
1 0 lineto
closepath
} def
/inch {72 mul} def
gsave
1 inch 6.5 inch translate
1.25 inch 1.25 inch scale
unitsquare fill
grestore gsave
4.25 inch 3.25 inch translate
60 rotate
2 inch 2 inch scale unitsquare
1 20 div setlinewidth stroke
grestore
4.5 inch 2 inch translate
-45 rotate
1 inch 2 inch scale
unitsquare .75 setgray fill
showpage
The QMS has BLACKs, while the blacks on the LaserWriter are a bit
washed out (especially unit black square) -- the 2x2 outline is quite
acceptable. More interesting was how the 75% gray is rendered: the
LaserWriter is rendered with what appear to the naked eye to be small
triangles or checks, while the QMS renders it as parallel sloping
lines. It would be interesting to aim a spot meter at each and see
which is closer to a true 75% gray; I personally prefer the appearance
of the LaserWriter's gray tone.
I noticed when I overlaid the two pieces of paper that all the shapes
and orientations are exactly the same (no surprise) but the page
offsets on the two devices are different. The LaserWriter prints
approximately 3/8" to the right and 1/4" further down the page than the
1200A (or, if you prefer, the 1200A prints 3/8" farther to the left and
1/4" further up the page.) I have no idea why, but this may be annoying
to people who are trying to meet specific formats, and seems like a
mistake. Of course, this is a limited sample, and there may be some
initial setup that hasn't been done correctly (A4 vs US? Paper tray
inserted properly? Suggestions?)
In general, I'm impressed that they're as close as they are, and a
little disappointed that they're not perfect.
And really lusting after my copy of TranScript, wherever it might be.
Cheers,
chris
----------laser-lovers@uw-beaver (06/06/85)
From: mtu!karl@Glacier (Karl J. Ottenstein) From: karl@mtu (Karl J. Ottenstein) Newsgroups: fa.laser-lovers Subject: Re: QMS 1200A vs LaserWriter Summary: Expires: References: <8197@Glacier.ARPA> Sender: Reply-To: karl@mtu.UUCP (Karl J. Ottenstein) Followup-To: Distribution: Organization: Michigan Technological University, Houghton, MI Keywords: Apparently-To: glacier!laser-lovers@washington >From: Christopher A Kent <cak@Purdue.ARPA> > >We just got our 1200A hooked up, and our LaserWriter appeared last >week. We don't have TranScript yet, but we have typed in one or two >files from the Cookbook. I ran them off on both, and thought I'd report >on the comparison. The QMS was "professionally" installed, and perhaps >tuned somehow; we just took the LaserWriter out of the box and plugged >it in. > >This is the example PostScript code, in case you want to try it: > >The QMS has BLACKs, while the blacks on the LaserWriter are a bit >washed out (especially unit black square) -- the 2x2 outline is quite The LaserWriter gets blacker with time; there is also a contrast knob in the back. >I noticed when I overlaid the two pieces of paper that all the shapes >and orientations are exactly the same (no surprise) but the page >offsets on the two devices are different. The LaserWriter prints >approximately 3/8" to the right and 1/4" further down the page than the >1200A (or, if you prefer, the 1200A prints 3/8" farther to the left and >1/4" further up the page.) I have no idea why, but this may be annoying >to people who are trying to meet specific formats, and seems like a >mistake. Of course, this is a limited sample, and there may be some >initial setup that hasn't been done correctly (A4 vs US? Paper tray >inserted properly? Suggestions?) The page offsets can be changed by downloading a short PostScript program to the LaserWriter. This is probably described in the (additional cost) "Inside LaserWriter" manual; it is also in a manual for Adobe which they include with the (additional cost) PostScript language manual. To check which printer is "off": take one of the test pages which is printed when the LW is powered on [you can disable this feature through software] and fold it into quarters: the intersection of two of the panes should be at the intersection of your folds. Ours is a bit off, but it doesn't bother anyone so we haven't changed it. >In general, I'm impressed that they're as close as they are, and a >little disappointed that they're not perfect. > >And really lusting after my copy of TranScript, wherever it might be. I wonder if your purchasing department is the bottleneck, or is it Adobe? We received incredibly fast service from Adobe and are quite pleased.
nather@utastro.UUCP (Ed Nather) (06/07/85)
> >And really lusting after my copy of TranScript, wherever it might be. > > I wonder if your purchasing department is the bottleneck, or is it Adobe? > We received incredibly fast service from Adobe and are quite pleased. It's Adobe -- we're also waiting for Transcript. Should be along Real Soon Now. -- Ed Nather Astronony Dept, U of Texas @ Austin {allegra,ihnp4}!{noao,ut-sally}!utastro!nather nather%utastro.UTEXAS@ut-sally.ARPA
laser-lovers@uw-beaver (06/10/85)
From: Christopher A Kent <cak@Purdue.ARPA>
Ed Taft responded to my note with the following:
--------Begin Forwarded Message
From: adobe!taft@Glacier (Ed Taft)
Subject: Re: QMS 1200A vs LaserWriter
To: Christopher A Kent <Glacier!"cak@Purdue.ARPA"@Glacier>
Date: 4 Jun 1985 0946-PDT (Tuesday)
Cc: taft@Glacier
In answer to the specific technical issues you raised:
1. The two machines indeed use different halftone screens to render
gray. We have found that dot screens don't work well on the XP-12 (the
Xerox engine on which the QMS-1200A is based). The problem is twofold:
small dots (used for lighter shades of gray) don't fuse to the paper
because of the way the XP-12's fuser works; and the dot screens form
Moire patterns or other artifacts due to mechanical or electronic
noise. That is why we chose a line screen for the QMS machine. If you
would like to experiment with a dot screen, the basic screen definition
is:
60 45 {dup mul exch dup mul add 1.0 exch sub} setscreen
2. The margins are adjustable in both the QMS-1200A and the
LaserWriter; the setmargins operator in statusdict (documented in the
LaserWriter Advanced User's Supplement) sets them in both machines. It
is more likely that the QMS machine requires alignment. We never did
establish nominal margin settings for the QMS machine; the margins used
in the current "beta test" software were pretty much picked out of thin
air.
Ed Taft
--------End Forwarded Message
As for where our copy of TranScript is, I've found out. It's tied up in
litigation, believe it or not; apparently Purdue wants an
indemnification clause of some sort added to the contract, and Adobe
has taken the stand that the agreement is standard as it stands, and
won't pay more for lawyers to design a modification. Purdue claims that
it isn't standard without the clause, and seems ready to go to court to
prove it! I'm not going to express any opinions one way or the other,
just pass along the facts as they've been presented to me, so you can
all wonder, too.
Cheers,
chris
----------