Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!pasteur!agate!labrea!decwrl!mejac!gryphon!richard
From: richard@gryphon.COM (Richard Sexton)
Newsgroups: comp.sys.amiga
Subject: Re: Paint Jet Printers
Summary: colours
Keywords: os.2, paskal, pieracy, whackofftosh, modulus-2, hi bob!
Message-ID: <9659@gryphon.COM>
Date: 16 Dec 88 04:27:11 GMT
Reply-To: richard@gryphon.COM (Richard Sexton)
Distribution: na
Organization: Trailing Edge Technology, Redondo Beach, CA
Lines: 46

In article <1614@fbog.UUCP> dbk@fbog.UUCP (Dave B. Kinzer @ Price Rd. GEG) writes:
>
>I have a ThinkJet printer (thanks for the printer driver in 1.3!!) with
>the same type of disposable print head.  The head works by applying current
>through a resistor next to a tiny ink chamber.  This heats the ink until it
>vaporizes, forcing the ink in the nozzle to squirt to the page.  HP went
>to great lengths (as described in one of their journals) to create an ink
>with just the right properties (viscosity, surface tension, condensation
>to liquid when the vapor bubble cools, etc.)  It seems unlikely that
>an off the shelf ink would be very sucessful here.

Exactly. The formulations of the inks is a very precise science and the
tuning of the colours is an art. The Xerox inks are water, pigment
and a bit of propylene glycol. The Canon inks are alcohol based.

I'm not sure what the HP inks are. I found out what the xerox inks
wer made of by reading the manual - it had a product safty thing
in the back that told exacly how toxic everything was and even pointed
out that the $8 ``cleaning fluid'' was pure water. Ahem. I found out
that the Canon inks were alcohol base by calling cannon until I finally
got somebody who knew what I was talking about (generally hard to find).

I asked Nick Flor in San Diego HP, who wrote the firmware for the
printer what was in the inks and the pinhead babbled on about
``proprietry formulas''. Yeah right.

At any rate, the Canon inks make the worst colours (the red is orange, the
blue is purple and the green is a bit yellow), the Xerox is next (the
red is too cyan, the blue is too cyan), the HP is next, it has the 
same spectral defects as the Canon, just to a lesser extent.

Now, Tektronix. Oh Tektronix! Their inks are as perfect as I've ever seen
in an ink jet printer. If anyone A) can get some, B) knows if they'll
work in a canon printer, SPEAK UP!

> Of course, the
>Paintjet printer might work in an entirely different manner, but red,
>green and blue (and brown) inks are now available for the Thinkjet (sounds
>suspicious to me :-) :-)).

Sure does. For a decent review of subtractive vs. additive colour
systems (RG & B) vs. (CM & Y) check out section 17.4 in Foley and Van
Dam _Fundamentals of interactive computer graphics_. (Not to be
confused with _Principles of interactive computer graphics_)
-- 
               ``Wake me up when it's time to go to sleep''
richard@gryphon.COM   {...}!gryphon!richard   gryphon!richard@elroy.jpl.nasa.gov