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From: graeme@labtam.oz (Graeme Gill)
Newsgroups: comp.graphics
Subject: Re: GIF images lack gamma info too: (was pixel aspect ratio in GIF images)
Summary: What I had in mind in the original posting ...
Message-ID: <5047@labtam.oz>
Date: 25 Jul 90 04:21:43 GMT
References: <9866@pt.cs.cmu.edu> <9894@pt.cs.cmu.edu> <1990Jul24.124203.10040@eagle.lerc.nasa.gov>
Organization: Labtam Limited., Melbourne, Australia
Lines: 21

In article <1990Jul24.124203.10040@eagle.lerc.nasa.gov>, fsfacca@ZoSo.lerc.nasa.gov (Tony Facca) writes:
> 
> This value is call the "gamma" of a monitor and is said to be between 1.4 and 
> 3.0 depending on the type of monitor.  I am not sure what the original poster
> had in mind when he suggested adding a "gamma" value to the GIF description.
> 

	What I was pointing out was that there is a similar problem with image
brightness as there is with pixel aspect ratio. ie - in trying to display
a GIF images from some other system, you run it through your favorite
GIF display program and look at the image - and find that, Hmmm - the aspect
doesn't  look right, and uh - it looks very dark (or bright).
	The solution is for these characteristics (pixel aspect ratio and
intended display gamma) to be documented in the image, so that the display
program can correct for the assumptions without trial and error fiddling
at display time  - and you can then be sure of viewing the image the way
its creator intended.

			Graeme Gill

			graeme@labtam.oz.au