Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!tgingric
From: tgingric@magnus.ircc.ohio-state.edu (Tyler S Gingrich)
Newsgroups: comp.sys.next
Subject: Re: Colour Palette on a ColorStation
Message-ID: <1991Apr19.191225.29859@magnus.acs.ohio-state.edu>
Date: 19 Apr 91 19:12:25 GMT
References: <SPINNER.91Apr12100158@wpi.WPI.EDU> <32370001@hpcuhe.cup.hp.com>
Sender: news@magnus.acs.ohio-state.edu
Organization: The Ohio State University
Lines: 57
Nntp-Posting-Host: right.magnus.acs.ohio-state.edu

In article <32370001@hpcuhe.cup.hp.com> edwardm@hpcuhe.cup.hp.com (Edward McClanahan) writes:
>Sam Streeper explains:
>
>> ----- Begin wayward color lookup table discussion --------------
>> 
>> By the way, NeXTstation hardware does NOT utilize color lookup tables.
>> In other words, every pixel has a specified color rather than an index 
>> into a table that specifies the color.
>> 
>> If a system has 256 colors onscreen from a pallette of 4096, that means
>> every pixel has 8 bits specifying an index into a color table
>> with 256 entries, each of which is a 12 bit color specification.  Color
>> lookup tables have a few keen features, but they can also be a big pain
>> in the rear.
>
>This may be misleading, however.  Just because a system can display all
>4096 possible colors on the screen at the same time (from a "pallette" of
>4096 colors) does not mean it LACKS a Color Lookup Table.  One justification
>for a CLT pointed out several months ago that it can be used to tweak the
>mapping (away from 1-to-1) to allow for deficiencies in the D->A converter
>and the relative strengths of the RGB guns (as well as the surrounding
>lighting).
>
>Also, it is possible to modify entries in the CLT during the page update
>cycle (i.e. as the display hardware is reading the pixel "values" from
>memory, using these "values" to index into the CLT to find the Digital RGB
>values to convert to Analog values to send to the RDB guns in the monitor).
>Obviously, this method must be applied every screen refresh (30-?? times
>per second).
>
>So, I still have not heard a definitive statement as to the lack or
>existence of a CLT on the NeXT (4-bit mono, 12-bit color, or 24-bit color).
>Does anybody know for sure?
>

Just to add fuel to this fire, stir the pot, and generally create havoc and 
confusion throughout the civilized world........  

The following is taken (without permission) from the NeXT add on pages 32/33
of volume 5 number 14 MacWEEK (4/16/91):


  "......
   If, on the other hand, you choose to go 
   the NeXTstation Color route, you'll have
   the option of enhancing your presentation
   with your choice of over 4,000 colors from
   a palette of over 16 million.
   ...."

So, either the color station does some sort of 'color-lookup' or the marketing
folks at NeXT don't know their machines.  (Yes, I agree, this is VERY possible)

Tyler

PS: I've seen a demo color station.  I WISH I could afford one.  All I have
is a mere NeXTStation.....    :-)    :-)    :-)