Path: utzoo!censor!becker!bdb
From: bdb@becker.UUCP (Bruce Becker)
Newsgroups: comp.sys.amiga
Subject: Re: Paint Jet Printers
Message-ID: <200@becker.UUCP>
Date: 7 Jan 89 07:07:24 GMT
References: <158@pande.UUCP> <2629@wang7.UUCP>
Reply-To: bdb@becker.UUCP (Bruce Becker)
Distribution: na
Organization: G. T. S., Toronto, Ontario
Lines: 59

In article <2629@wang7.UUCP> you write:
+-----------------
|[...]
|What we have is a color science problem.  It is not trivial.  Yes, we did
|it "correctly" at Eikonix, but we used 3 array processors and a PDP-11 to
|acheive our results.  Not very practical for "affordable solutions" on low
|cost equipment, eh?
|
|If you're feeling really masochistic, pick up a copy of "Color Science:
|Concepts and Methods, Quantitative Data and Formulae" Second Edition by
|Gunter Wyszecki and W. S. Stiles.  Copyright 1982 John Wiley & Sons, Inc.
+-----------------

	Dam' pricey she is - Anybody like to sell me a used one?

+-----------------
|Keep in mind that all of this discussion about "Orange Reds" vs. "Red Reds"
|is extremely subjective.  Color Science attempts to add a certain amount
|of objectivity to the human perception of different wavelengths of light.
|Red is Red and Blue is Blue simply because we say it is.  If that isn't
|subjective, I don't know what is.
|
|In summary, to get from the screen to the printer, you want to accurately
|map an additive color space (RGB) to a subtractive color space (YMCK)
|You need to know the characteristics of the phosphors in your CRT and you
|need to know the characteristics of the ink AND paper in your printer.  In
|a graphic arts shop, they even know the characteristics of the light source
|they use to view proofs!  Finally, you need a whole hell of a lot of compute
|horsepower to get from point A to point B.  IF you do it right, you should
|be able to view soft copy and hardcopy side-by-side, under controlled
|conditions, and not see any difference in color.
+-----------------

	Also read Oct. 88 issue of ACM Trans. on Graphics, Vol. 7 # 3.
	"Color Gamut Mapping and the Printing of Digital Color Images",
	by Maureen C. Stone, William B. Cowan, & John C. Beatty, pp 249-292.

	This paper was first presented in 1986, but it's still way
	ahead in a lot of ways - it also leaves a lot of issues open,
	more or less left as an exercise for the reader 8^)...

	Also see Appendix III of Raster Graphics Handbook, 2nd. Ed.,
	by Conrac Corp. (Van Nostrand, 1985). This gives the
	RGB to CIE transforms & covers the basic issues of
	color programming (but not all the subtleties)...

+-----------------
|Kevin McBride         Another  //     | A cure for AIDS has been found.
|Wang Laboratories      Proud  //      | They've given it a Yamaha part
|Desktop Image Systems     \\ // Amiga | number so now noone can get it.
|...!ima!wang7!klm          \X/  owner |       - Motorcyclist Magazine
+-----------------

Cheers,
-- 
   _  _/\	Bruce Becker	Toronto, Ont.
   \`o O|	Internet: bdb@becker.UUCP, bruce@gpu.utcs.toronto.edu
    \(")/	BitNet:   BECKER@HUMBER.BITNET
---mm-U-mm---	"The OSF is suffering from Penix envy" - Rocky Raccoon