Newsgroups: comp.arch
Path: utzoo!utgpu!watserv1!watcgl!imax!dave
From: dave@imax.com (Dave Martindale)
Subject: Re: Resolution, etc.
Message-ID: <1990Nov19.195042.19240@imax.com>
Organization: Imax Systems Corporation, Oakville Canada
References: <240@csinc.UUCP> <1990Nov15.052925.1265@imax.com> <2928@crdos1.crd.ge.COM>
Distribution: na
Date: Mon, 19 Nov 90 19:50:42 GMT

In article <2928@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.com (bill davidsen) writes:
>
>  I'm not convinced that you need 24 bits of color for the memory,
>either. Systems like the VGA which have a large palette and a limited
>number of selections work very well. If you look at the output of a 24
>bit color scanner scanning quality photographs, you rarely find an image
>which doesn't map into 256 colors nicely. Very rarely.

I guess it depends on what you're doing.  This certainly isn't true when
dealing with "photographic-quality" images.  When digitizing transparencies
or negatives, 24 bits is clearly not enough - I can show you images with
ugly banding artifacts due to quantization in the dark areas of the image.

Even digitizing at 36 bits (12 bits/component) and then storing 8 bits
of the logarithm of intensity is not enough in some circumstances.

>  Therefore I conclude that for human viewing of "real world" images
>(ie. things which physically exist) you can do 8/24 bit mapping with
>good results.

I suspect we have different definitions of "acceptable".  Mine is
"you can't see any artifacts due to the transfer from film to digital".
Yours may be "it looks pretty good".  This may be adequate for
most people dealing with images, but it certainly isn't good enough for
everyone.

I currently use two monitors - 1600x1200x1 monochrome for editing, and
1024x768x30 colour for image display.  This seems like a pretty good
compromise for the moment - high resolution and fast drawing for text,
while colour images appear much more slowly but with excellent quality.

	Dave