Am 29.12.2017 um 09:42 schrieb Jörg 'Yadgar' Bleimann:

> Which leads me to the next question: Does POV-Ray's
> eval_pigment() also handle 16-bit grayscale pngs correctly?

Absolutely. Everything you can use in a pigment, eval_pigment() will
handle correctly - for technically feasible definitions of "correctly".

Beware however the gamma monster. When using images as terrain elevation
maps, you'll typically want linear values. Ideally, the generating
software should use linear encoding and set the `gAMA` chunk
accordingly, but not all software is that well-behaved. To be on the
safe side, specify "gamma 1" in the image map. (Unless the generating
software uses non-linear encoding.)

(When using images in genuine height fields or bump maps, "gamma 1" is
the default. But for eval_pigment() you'll need to load the image as a
pigment first, in which case POV-Ray defaults to whatever gamma is
indicated in the PNG file, or sRGB if the file doesn't contain gamma
information.)

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