Am 02.01.2012 17:47, schrieb Warp:

>    So why shouldn't gamma correction be used for this purpose?

Depends on what you want to do. For realism, there is one simple rule: 
Just don't. Gamma adjustment (you definitely can't call it "correction" 
in this context) doesn't just adjust midtone brightness - it also messes 
with saturation and hue. For instance, darkening an image this way will 
increase color saturation while shifting hues towards the primaries 
(i.e. red, green and blue). If that is really what you want - just go 
ahead. But as for adjusting image brightness, I'd instead recommend 
rendering to OpenEXR and then using an external postprocessing tool that 
knows its job.

(There /is/ one legit gamma adjustment use case that hasn't been 
discussed yet: Viewing conditions differing significantly from the 
reference conditions specified in the sRGB standard require the gamma to 
be tweaked accordingly to ocompensate; otherwise, e.g. when viewed in a 
pitch black room the image would look too pale; however, the sRGB 
standard considers this a duty of the viewing equipment, not the image 
generating software, and I fully agree.)

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