On Sun, 12 Nov 2000 21:14:20 +0100, Jan Walzer wrote:

>So this is what I originaly ment ... If you use the
>gamma-correction(with negativ values) on an antialiased image ,
>you don't have any longer the effect of antialiasing. The GC
>could produce again (unexpected) stairsteps.
>
>But: AFAIK Gamma is only defined for values > 0 ...
>
>So does it make sense to ask if the current model is correct ???
>Of course, we often have other functions in POV, working with
>unrealistic values (negative pigments or lights ...[New question:
>what is with negative IOR ???]), but they are or could be quite
>predictable, but what do you expect from a negative gamma value
>??? How would define the result ???
>
>BTW: has someone here have the code for the gamma function ???

Don't think I understand most of your questions but this should
answer some.  The attached image was gamma corrected in a graphics
package, to -1.6, and I get exactly the same results as using
negative gamma in pov.

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