Am 05.03.2012 00:25, schrieb JamesB7271:

> Thank you so much for the detailed response. I of course want the most realism,
> so I do want to make sure I'm getting started right.

In that case, assumed_gamma 1.0 is /definitely/ the thing you want.

> Below is a simple sample scene (partly from the tutorials). If I render it as
> shown below, it looks too bright and washed out to me. However, if I change the
> "#version" statement to 3.6, or change the "assumed_gamma" statement from 1.0 to
> srgb, the scene seems to look more realistic. Can you try it and give me your
> opinion? If the new 3.7 gamma handling is the correct and more accurate method,
> then I think I may be doing something else wrong?


I personally find nothing wrong with the scene you provided, when 
rendered with POV-Ray 3.7 and "assumed_gamma 1.0"; to the contrary, I 
find the result of "assumed_gamma srgb" unrealistically (and 
undesirably) dark.

Essentially, there are three possible reasons why you might think the 
image is too bright:


(1) The image as computed by POV-Ray might be fine, but what you see is 
not what POV-Ray computed, because your system's display pipeline (i.e. 
Windows color management settings, graphics driver settings, graphics 
card and display hardware properties) and/or the image viewing software 
might introduce some "color distortions" that POV-Ray isn't aware of.

POV-Ray 3.7 comes with a sample scene named 
"scenes/gamma/gamma_showcase.pov" which is specially tailored for 
identifying this type of problem.

Make sure your Windows screen settings are configured to use your 
display's native resolution. Render the scene at 640x480 resolution and 
display it at 1:1 zoom; from a distance, the left and right hemispheres 
of each sphere in the image should look uniform in color, saturation and 
brightness. (Close inspection of the image however will reveal that most 
of them are not: The right hemispheres are actually striped 
horizontally; that's perfectly intentional.)

If on your system the left hemisphere of each sphere appears 
significantly brighter and/or more washed-out, fixing your display 
settings (black-/whitepoint and gamma) might solve your problems; you 
can find plenty of sites on the Interwebs to help you with this.


(2) The colors in the scene might simply /be/ brighter and more washed 
out than you'd like them to be. In that case, try...

... choosing more saturated colors (might be difficult for the yellow 
ball, but you can probably do something about the marble floor; a good 
bet might be using "srgb" wherever the material currently uses "rgb"; 
you might need to copy the materials from the default .ini files for this);

... reducing the global_settings { ambient_light ... } parameter 
(default is 1.0) and/or your materials' finish { ambient ... } setting; 
especially the latter is typically quite high in old materials, as they 
were designed to look good with the de-facto too dark image results as 
computed by POV-Ray 3.5 (or 3.6 with default settings); better yet, use 
radiosity (with 3.7, this will automatically turn off the ambient 
mechanism);

... using fade_distance and fade_power for a realistic distance-based 
fading of the light. (Rule of thumb: Set fade_power to 2, set 
fade_distance to the size of your area light, and increase (or in rare 
cases decrease) light intensity to achieve the desired overall 
brightness level. (Don't be surprised if you need to set the nominal 
brightness of the light source to some pretty high value.)


(3) You might have become so accustomed to 3.5's rather dark results 
with deep shadows that the old look feels more realistic to you than it 
actually is. In that case you'll need to either get used to realistic 
renders again, or abandon realism and go for artistic freedom instead.


 From a distance I can't tell which of the three is the case (and I 
wouldn't be surprised if it's actually a combination of all three of 
them), so - as I already mentioned - you should first check your display 
settings.

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