Newsgroups: comp.graphics
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From: bcorrie@csr (Brian  Corrie)
Subject: Re: Gamma correction (Used to be: Radiosity Image Correction)
Message-ID: <bcorrie.675454325@csr>
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Organization: University of Victoria
References: <1991May27.135349.5072@vax5.cit.cornell.edu>
Distribution: comp
Date: 28 May 91 18:12:05 GMT

wuly@vax5.cit.cornell.edu writes:
[Stuff about Radiosity problem deleted]

>I have found that gamma correction does wonders for me, and my images are
>darker than most due to inaccurate (too low) energy transfers (it made
>calculations very fast, though).  For those of you using more accurate
>routines, a gamma correction style transformation during color assignment
>should be helpful.

Kind of a different but the same question.... I have been using SUN
workstations to display generated images over the last couple of years. We
recently got a NeXTstation Color. I convert the 24 bit SUN files to tiff
files and display them on the NeXT, and the images are a lot darker than
the images as they are displayed on the SUN.

The difference is quite significant (to the point that the image isn't
really worth looking at). My question is, is this a problem that could be
solved by gamma correction, or is it likely a result of the conversion
process? Anybody?

You may have guessed that I am not an expert in Gamma correction. I always
thought it was a detail for those who are perfectionists, and want an image
to look identical on every monitor. Is it possible that not doing gamma
correction on an image could make this much difference?

Note: Some of the images are much worse than others, but all are definitely
darker on the NeXTstation color than they are on the SUNs.

>For my case, a gamma correction of 1.8 looks nice, but of course that depends
>on the monitor and the image.

>wuly@vax5.cit.cornell.edu

Thanks for any help you can give me,

	B

P.S. Is this a question for comp.graphics or comp.graphics.research? To me,
it isn't research, nor is it an inquiry about research, its an enquiry about
a fact. Therefore, it belongs in comp.graphics. I hope the experts don't stop
reading comp.graphics so these questions will still be answered.

--
                  Brian Corrie (bcorrie@csr.uvic.ca)
Under the most rigorously controlled conditions of pressure, temperature,
volume, humidity and other variables, the organism will do as it damn well
pleases. Sounds like some of the code I have written......  8-)
