"epidot" <nomail@nomail> wrote:
> I wonder if it is possible to use the transmittance/absorbance spectra of a
> liquid in povray? I've got some data for some liquids that I would like
> rendered.
>
> Also ... is there a way to use standard illuminants, such as d65, C etc?
>
> Thanks for your help

Uh... I have no idea about "standard illuminants", but I guess what you're
trying to do would need a render with more spectral "bands" than just "Red",
"Green" and "Blue".

An idea how to achieve this would be a multi-pass render with a "false-color"
approach. Who said that the three components in a color vector are "Red",
"Green" and "Blue" anyway? Could be any spectral "band" you choose, e.g. three
particular "Fraunhofer lines" or whatever you like.

So wherever you'd normally use a color, you could instead use a macro with, say,
12 or 24 parameters representing spectral components, which picks a subset of
three depending on the render pass.

This way you'll end up with a bunch of false-color renders of your scene, which
you can then post-process in gimp, photoshop, or a properly designed
orthographic scene, by splitting up the three channels of each image into b/w
separate layers, multiplying each with the corresponding spectral band's
contributions to percieved RGB, and mixing finally mixing all the resulting
layers.


Alternatively, you might simplify the post-processing step at the cost of quite
some rendering time, by designing the macro so that it picks just a single
spectral band per pass, and already computes an RGB value from it. (Given that
R and B don't overlap too much, you might also be able to "cheat" a bit and
process two bands per pass, one in the "R/G" domain and one in the "G/B"
domain.)

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