On 10 Dec 2000 11:46:40 -0500, ingo wrote:
>Margus Ramst wrote:
>
>>And for example radiosity lit "blue sky" outdoor scenes do tend to look
>>unrealistically blue IMO, so despite my limited knowledge of physics I
>>must assume there is some aspect of natural light behaviour not
>>provided for here. 
>
>In the real world there is no direct "colour-bleeding" from the blue sky. 

There is, but see below:

>It where nice if it was possible to switch off the lolour of the bleeding 
>from the "sky_sphere" in POV.
>
>Photorealism: these blue pictures look as if an outdoor scene was 
>photographed with a film suitable for artificial light.

Exactly. Sunlight is a lot more blue (or less red) than artificial
light. The human eye adapts to these differences, but film - or povray -
cannot. Therefore you need different films for indoors and outdoors to
get lighting, which "looks right". Similarly, would need different
settings in povray to simulate the adaptation of the human eye to
different lighting.

	hp

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Chris Huff wrote:
> 
> In article <Xns### [at] povrayorg>, ing### [at] homenl (ingo)
> wrote:
> 
> > In the real world there is no direct "colour-bleeding" from the blue sky.
> 
> I believe you are mistaken...most of the illumination in the shade comes
> from scattered light. And things lit with sky light *do* have a blue
> cast, but your eyes usually adjust to it.

Agreed.  Look at shadows on fresh snow.

-- 
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Francois Labreque wrote:

>Look at shadows on fresh snow.

The snow in the shadows has a bluish tint, the rest of the snow is 
"white". The general lightning is white, due to atmospheric scattering the 
shadow is blue.
When radiosity rendering with a blue sky_sphere it is as if the light is 
blue. The snow and the shadow are blue.

This is why I stated: "In the real world there is no direct "colour-
bleeding" from the blue sky", probably needed to put more emphasis on 
"direct".



Ingo

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Margus Ramst <mar### [at] peakeduee> wrote:
: And for example radiosity lit "blue sky" outdoor scenes do tend to look
: unrealistically blue IMO

  That's probably because people tend to make their skies unrealistically
blue and bright.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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