"Kenneth" <kdw### [at] gmailcom> wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> > Hi Kenneth - this is something that I was concerned about, tried to
> > address, and IIRC, did it backwards.
> >
>
> And you are correct-- your two macros are *reversed* as to their respective
> operations! Through no fault of your own: the Wikipedia formulae themselves are
> REVERSED...
>
Well, I never like to base my ideas on a single source of information, so I
looked at other web sources that have these 'color conversion' equations-- and
ALL the sources I've seen match the order of the equations in Wikipedia.  So I'm
obviously wrong about the two equations being 'backward' there. I gave this a
lot of thought, and realized that it's our *use* of those equations **in
POV-ray** that makes them seem so. To really explain why would take paragraphs,
and I'm still wrapping my brain around it. And I might put Ash to sleep... :-P

But the re-edited macros are still correct for their use in POV-ray... a
consequence of this 'new thinking'.

This NVIDIA article really opened my eyes to the correct way of visualizing the
situation, although it may not be immediately obvious...

https://developer.nvidia.com/gpugems/gpugems3/part-iv-image-effects/chapter-24-importance-being-linear

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