POV-Ray : Newsgroups : povray.general : Bits_Per_Color of rendered image-- wrong bit-depth reported : Re: Bits_Per_Color of rendered image-- wrong bit-depth reported Server Time
18 Oct 2021 17:29:07 EDT (-0400)
  Re: Bits_Per_Color of rendered image-- wrong bit-depth reported  
From: Kenneth
Date: 27 Sep 2021 16:50:00
Message: <web.61522d241680b35a4cef624e6e066e29@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "Kenneth" <kdw### [at] gmailcom> wrote:
> > I'm still testing the various .png bit-depths (by generating test images for
> > height_fields)...
> If I were to do it, I'd make a staircase from one side of the source image to
> the other and look at the resulting heightfield from the side.  Then it would be
> a "graph" of the numerical data.  Contrasting gridlines would eliminate any
> ambiguity int the visual judgement part.

Heh heh, that was exactly my thought as well, although I ended up using a
slightly different method. Brilliant minds named Walker sometimes think alike--
well, uh, every now and then-- you usually think circles around me, ha.

*Ideally*, for testing a 16-bit grayscale-output image (to then make a
height_field for examination), I would need to render at least the vertical
dimension of the image at a res of 65,536 pixels-- to *clearly* see the steps
vs. some other bit depth. I actually tried such a test-image render-- and
POV-ray crashed and burned :-O   I kind of expected that.

SO, thinking more practically, I rendered a 2500X2500 image using the 'bumps'
pattern... testing every bit-depth from 4 - 16... then exaggerated the height of
the resulting HFs and zoomed-in with the camera, to see the individual steps.
Not ideal, but successful.

I'm happy to say that POV-ray does indeed render its grayscale images at each
individual bit-depth. :-) With no 'gaps' re: the way that other image-viewer
apps are reporting it.

I can rest now!

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