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Contrast increase brightens image
Posted: Sat Aug 21, 2010 15:31
by olivepixel
I find that increasing the contrast with the Bright.Contrast effect tends to brighten the image, to the extent that the contrast modification on its own isn't really usable.
Is this a glitch?
Re: Contrast increase brightens image
Posted: Mon Aug 23, 2010 08:42
by Joris
Well, increasing the contrast increases the difference between the darkest and brightest parts of your image. It would make the bright parts brighter, and the dark parts darker. If you have an already bright image, increasing the contrast would indeed make it brighter overall.
Re: Contrast increase brightens image
Posted: Mon Aug 23, 2010 09:08
by olivepixel
goto10 wrote:Well, increasing the contrast increases the difference between the darkest and brightest parts of your image. It would make the bright parts brighter, and the dark parts darker. If you have an already bright image, increasing the contrast would indeed make it brighter overall.

- contrast.jpg (224.53 KiB) Viewed 5581 times
But it seems that it doesn't behave as expected; to get a usable contrast increase you have to decrease the brightness by as much as you increase the contrast. It's an ok workaround of course, just means mapping twice.
Re: Contrast increase brightens image
Posted: Tue Aug 24, 2010 07:53
by Joris
Thanks for the screenshots, and the comparison with the same filter in Photoshop! I guess it'd be better if both filters/effects would work similarly, so I'll make a ticket out of it.
Joris