> I'm going to jump in here and hopefully I won't look too foolish .... 
> however I think the top row looks more like what I'd expect.

Because you are used to how POV handles colours :-)  But seriously, in the 
top row, the *colours* (not brightness) are actually different from what you 
specified in the SDL.  It is easiest to see this with the orange ball, 
anybody trying to make some promotional material where the colours need to 
be accurate for a certain brand (eg the Sony Ericsson "orange") would likely 
get the top row thrown back at them for being the wrong colour.  The bottom 
row preserves the correct colour.

The reason is that for "colours" (where RGB are not equal), gamma will 
modify the brightness of each channel a different amount, so you are 
actually changing the colour that you see, not just the brightness.  Your 
eye is very sensitive to changes in colour, even when the brightness is 
different.

> brightness looks to low to me. contrast compares with top row.

The brightness is easily controlled by the diffuse value in the finish 
statement, or by cranking up the light colour.  Maybe I should have rendered 
with more brightness to avoid the confusion between change in brightness and 
change of colour?

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