kirk@kalalau.berkeley.edu (Kirk Thege) (11/16/90)
A couple of eons ago, I posted a request for comments about color printers. I only received a couple of replies. (Do you suppose the screwed-up return address in my original posting had anything to do with it?). I've summarized the postings below. -Kirk -------------------------------------------------------------------------------- Mike Smith (SMITHM@QUCDN.QueensU.CA) replies: Last Spring, I had use of a QMS ColorScript 100 for about a week. (We borrowed it to exhibit in our bi-annual "Open House".) The 100 is a thermal wax transfer printer, achieving colour with a four pass (assuming cymk film) process. The quality was quite pleasing, the consumable cost is fairly expensive, about $CAN1.00/page. My recollection is that a page took about 90 seconds to print. At the time, our price was about $CAN10,000. The QMS prints on a *very* smooth paper or transparencies. The consensus seemed to be that the latter was the most desirable output medium. At the show there was lots of interest in us buying one as a central resource. Of course, the show was too late for our budget year so, if we get one at all it would be next summer. -------------------------------------------------------------------------------- Mike Murphy (sceard!mrm@ucsd.edu) replies: The best thing to do with the color printers is to look at some sample output. None of them yet looks like a printed page from a magazine :-) What you like may not be what I like. All of the technologies that I've seen look pretty Rube Goldbergish when viewed from inside. The only real warning I would have is to check out the quality as a function of time. That's hard to do. What I mean is that the inks and dyes age. The different colors age (oxidize, fade, whatever) at different rates, so that a page that was in perfect color balance when printed looks too red or too blue or too yellow after a month or two. Another thing to watch for is the migration of the dye or ink on the medium (same thing as chromatography), that is, the adsorbtion coefficient of the dyes may differ for different colors. What you then see is bleeding and haloing. You may also get to notice first hand that dye and ink chemists mix different chemicals to get just the color that they want. This means that what may be a pure, single color as far as your color bitmap is concerned, say yellow=0, magenta=1, cyan=0, may end up being a mixture of chemicals on the page. Then comes the ageing and bleeding. (Yellow, magenta, cyan) and (yellow, red, blue) with optional black thrown in are the primary colors you'll probably encounter. RGB is for transmitted light, e.g., a CRT. RGB with finger paints on paper makes it tough to get yellow :-). I was kind of amused to see a company spend a pile of money on a printer and then supply it with an RGB ribbon. No yellow possible...ever. YMC and YRB are equivalent, simple matrix transformation to switch an image from one to the other. The technologies that you'll see: 1) Wire dot matrix printer with multi-color ribbon. I like the JDL. Another good one is the Advanced Matrix Technology Office Printer. The low end printers like the Citizen are really a good deal for the money (<$500). Inks are pretty stable, and the resolution for the expensive ones like the AMT OP are high (480x240dpi). 2) Ink jets. Take a look at the HP PaintJet (low cost but good, more money doesn't always mean better). A PaintJet or two on a cheap 286/386 with PostScript on the 286/386 and Ethernet may be a better thing than an expensive PS color printer, if you're clever with the setup. The best inkjet I've seen is the Tektronix. Even better with the PS controller. It's more money 3) Hot wax. The cheap ones are pretty bad. The Tektronix is pretty good. I don't care for the shiny surface paper and splashy bright color, but that is only personal preference. You may like it. 4) Xerographic powder. More money. Better quality (maybe:-). Take a look at QMS, they seem to be the most popular. Also check offerings from the big engine manufacturers, e.g. Canon. All of the PS implementations that I've used have bugs. Mostly you can work around, but if you're using a canned software package that won't stuff the PS text into a file so's it can be tweaked, and if you find a bug, it's tough to fix it or to work around. -- Kirk Thege Electronics Research Lab ucbvax!zabriskie!kirk 400A Cory Hall kirk@zabriskie.berkeley.edu University of California (415) 642-0312 Berkeley CA, 94720 Onward ... thru the fog