I am slowly working towards an understanding about what needs to be 
done. The skies.inc was primary exploration for me; I have now examined 
more closely some texture issues.

I selected the American Granites suite which Daniel Mecklenburg Jr wrote 
for version 2.2. I corrected some inconsistencies and then built a 
#switch system (for now only the first textures: MohoganyPol and 
MohoganyFro) to allow for different renders according to the user's whim.

I think that this suite of granite textures should be included into the 
POV-Ray package by the way. I guess it was dropped or lost.

The image below shows two sets of renders: The top two rows correspond 
to the MohoganyFro set; the two bottom rows to the MohoganyPol set. The 
difference between the row couples is only that in the second one a 
layered texture is used for some extra veins in the granite.

The first column shows the granite in its basic, linear colour space, 
form as written by the author.

The second column uses a simple rewrite of rgb --> srgb, assuming that 
the original code was written for an assumed_gamma 2.2 environment.

The third column uses the transformation function by Ive from scRGB to 
sRGB. I kept this column as reference, but I would argue for the 
following column as to be definitive.

The fourth column additionally uses the colour saturation/brightness 
variation code by Clipka.

It is a bit of work, but I think that this would be an acceptable to 
update the textures available in the Include directory.


-- 
Thomas

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