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I would like to use Povray to render nice-looking graphics of molecules, which can be exported from visualization softwares like Jmol. However, I have noticed that the color of the rendered graphics looks brighter compared to the visualization in Jmol itself. (see image below) Is that something expected? And is there a way to adjust the brightness so that the brightness remains the same as in Jmol?

enter image description here

P.S. After some investigation, I believe I have located the cause of the problem (but have still not resolved it yet, see images below): In the render preference, there is a "Gamma" option which controls the brightness of the rendered image, but no matter what value I put in here, the value of Gamma in the final rendering window is always 2.5, which is too high (it should be ideally around 1). I would really appreciate it if someone could suggest how to correct this behavior. This problem appears with Povray 3.8 on MacOS.

Seems that the brightness has nothing to do with the Gamma value after all (tested with Povray 3.7), so the problem remains.

enter image description here

enter image description here

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  • $\begingroup$ I use the following options and everything ran fine: +SP8 (start with every 8th pixel), +Q8 (quality is high), +A0.3 (anti aliasing), Antialias=On, Antialias_Threshold=0.3. $\endgroup$
    – Camps
    Jan 17 at 0:31
  • $\begingroup$ @Camps May I ask where do you add these options? Is it in the command line? (sorry I'm not an expert in Povray) $\endgroup$ Jan 17 at 0:41
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    $\begingroup$ I am not an expert either. I add such parameters inside a file called par.ini, then, from Jmol console, after loading my system, I wrote: write POVRAY file.pov. Finally, from the Linux prompt: povray par -Ifile.pov -Ofile.png $\endgroup$
    – Camps
    Jan 17 at 1:21

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Just found the answer myself: simply adding the line

global_settings { assumed_gamma 2.0 }

in the *.pov file makes all the difference:

Jmol + povray after gamma correction

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