Path: utzoo!utgpu!watserv1!watmath!att!rutgers!usc!csun!nic.csu.net!csus.edu!ucdavis!iris!zerkle
From: zerkle@iris.ucdavis.edu (Dan Zerkle)
Newsgroups: comp.sys.amiga
Subject: Re: 24/32 Bit Color
Message-ID: <7843@ucdavis.ucdavis.edu>
Date: 18 Oct 90 03:52:29 GMT
References: <33786@nigel.ee.udel.edu>
Sender: usenet@ucdavis.ucdavis.edu
Reply-To: zerkle@iris.ucdavis.edu (Dan Zerkle)
Organization: U.C. Davis - Department of Electrical Engineering and Computer Science
Lines: 31

In article <33786@nigel.ee.udel.edu> byrne@muppet.dnet.ge.com writes:
>
>I think I need some education.  I was under the (false?) assumption that the
>human eye could not distinguish 16 million colors (24 bit).

More like 14 million about.  I don't have the exact number handy.  It
depends on the person.  You can, however, distinguish about 116 shades
of pure yellow though.  You get 256 with 24-bit color....

>I assumed 24 bits
>was decided as number because it was an even multiple of a byte given the 3
>color components (RGB).

Very good.  Go to the head of the class.

>Since most displays don't have 16 million pixels, this
>[gives you a great big pallette.  But why 32-bit?]  (whoops, dz messed up)

The extra eight bits are used for information besides color.  For
example: on a NeXT, you get graphical objects floating around the
screen.  Sometimes, one object can be "in front" of the other.  In
this case, you want to know what is the depth of any particular
object, to know which one goes in front.  Also, you want to know the
transparency of any particular pixel.  You can actually move a
"translucent" icon in front of some other thing on your screen and see
the other thing partially obscured.  I hear you can drive a car across
your screen and see stuff through the windows partially distorted
colorwise....  

             Dan Zerkle  zerkle@iris.ucdavis.edu  (916) 754-0240
           Amiga...  Because life is too short for boring computers.