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May 20th, 2007, 07:13 PM
#1
Photoshop Adjust Brightness algorithm
What general algorithm do they use? When you brighten a dark image, it increases the luminosity of dark pixels more than the bright ones. The bright pixels are not allowed to reach or surpass full white.
Any ideas?
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May 20th, 2007, 07:48 PM
#2
Re: Photoshop Adjust Brightness algorithm
Preliminary testing shows that it is based on the luminosity histogram.
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May 20th, 2007, 08:02 PM
#3
Re: Photoshop Adjust Brightness algorithm
All it does is shift the luminosity histogram over.
The amount -100..0..+100 is the amount of the shift (where the historgam exists from 0..255). So, it has nothing to do with a %. It's just -100..100 of 255.
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May 21st, 2007, 07:35 AM
#4
Re: Photoshop Adjust Brightness algorithm
It's even more simple than that. It just adds x = -100..100 to R, G, and B, and bounds them to 0..255, with no regard to the fact the hue changes.
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