in news:3B7### [at] pphtvfi Kari Kivisalo wrote:
 
> All the data is non clipped. By scaling light source and ambient
> source intensities I can make sure the scene fits in 0-1 range.

The "studio-situation" form a photography view point.
So what you are doing is "gamma adjustment the hard way", but with more 
control over the result?

 
 Dens^          __
     |       --*       ***this curve is for negative material.
  D2 ____   /             for positive material (slide) mirror           
     |     /              the curve.
     |    /
  D1 __  /_a 
     |__/    |
     +---|---|------------> log H (light dosis)
     logH1  logH2
     
> So developing stretches the scene's intensity range down along the
> curve. Exposing stretches the range up along the curve. I just
> looked at linearised film response curve and concluded that it's
> just a typical compress operation. 

 Not quite, without any change in the light dosis, when the film is 
developed longer the gamma will be higher, the curve steeper. This only 
to a certain extend, there is a maximum density that can be reached for 
a certain light dosis. If developed longer the film wil get a to high 
background haze, that reduces contrast. Shorter development, flatter 
curve.
 Without change in development, a higher light dosis moves the 
highlights towards, or into, the shoulder. The shadows move from the 
foot towards the middle section. You'll lose detail in the bright 
parts. Lower lightdosis does the opposit and you'll lose detail in the 
shadows.
 For negative material goal is to always get the same gamma ( tang(a), 
(D2-D1/logH2-H1) ) that fits with the printing paper and enlarging 
apparatus used.

> Check: density=blackness ? :)

Yes 



Ingo

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