Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!sdcsvax!jww
From: jww@sdcsvax.UCSD.EDU (Joel West)
Newsgroups: comp.sys.mac
Subject: Re: Video memory and the Mac II
Message-ID: <4155@sdcsvax.UCSD.EDU>
Date: Fri, 23-Oct-87 11:11:31 EST
Article-I.D.: sdcsvax.4155
Posted: Fri Oct 23 11:11:31 1987
Date-Received: Sun, 25-Oct-87 15:07:04 EST
References: <11827@decwrl.DEC.COM> <6537@apple.UUCP>
Organization: Palomar Software, Inc., Vista, CA
Lines: 36

In article <6537@apple.UUCP>, lsr@apple.UUCP (Larry Rosenstein) writes:
> Color Quickdraw supports the old Quickdraw color model of 8 fixed colors and
> maps those colors into the closest available color..

I don't want to get picky (particularly with Larry), but
Color QuickDraw actually:

     *	maps the eight using 'clut' resource #0, which stores
	colors that approximate the ImageWriter II output
     *	then chooses the nearest available color from the 
	display's color table

With the 256-color video board, there's a noticeable difference
between these 8 colors and the fully saturated, pure eight:

	white
	red
	yellow
	green
	cyan
	blue
	magenta
	black

Of course, the IW II ribbon only supports cyan, magenta, yellow
and black, so the other colors (except white) are produced
by two-color combinations.

We put two orthogonal plots of this 8-color clut in an HSV (Hue,
Saturation, Value) cone in the Colorizer manual, and it turns
out that both the saturation and value for green are way off.
Also, magenta is reddish and cyan is bluish, so the IW II
manual calls these "purple" and "blue".
-- 
	Joel West  (c/o UCSD)
	Palomar Software, Inc., P.O. Box 2635, Vista, CA  92083
	{ucbvax,ihnp4}!sdcsvax!jww 	jww@sdcsvax.ucsd.edu