>> All I know is that when I take a dark image and try to make it 
>> brighter, it comes out hopelessly noisy.
> 
> That is probably because you took it with a camera that is already 
> hopelessly noisy, of course brightening it digitally is just going to 
> amplify the noise too.

Well, my camera *is* quite noisy. (More precisely: my camera takes very 
dark pictures unless used in insanely bright lighting conditions, or on 
a very long exposure.) I quickly learned that there is really no point 
attempting to take the beer-like shots it takes and make then viewable. 
All you get is signal noise.

But then, isn't film inherantly noisy too? And especially a scanned 
image, complete with dust and a rough surface...

> Try playing about with a better photo, (googling "photo" is a start!), 
> darken it by a factor of 4, then lighten it back to its original.  
> Hardly any noise visible.

Heh, not even DCT artifacts? :-P

-- 
http://blog.orphi.me.uk/
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