Correcting uneven exposure across an image

Ilya Razmanov · Post by **Ilya Razmanov** » Fri Jul 28, 2006 12:51 pm

I have the plugin that may help:

http://photoshop.msk.ru/aspd/

but it ain't free. Also, you may try playing with this:

http://photoshop.msk.ru/as/highpass.html

and see if free part of it functionality is sufficient for your needs.

And obviously, both of them will work only if you <i>really</i> have some useful signal in over\underexposed areas of your image. If they are like flat pure white\black areas, no software will recover the signal which is not there.

Post by **HaraldHeim** » Fri Jul 28, 2006 3:30 pm

You can fix it by dublicating the image on a new layer, adding a layer mask, drawing a gradient on the layer mask with the gradient tool and the adjusting the brightness of the new layer with the Levels tool.

I hope that helps.

Ilya Razmanov · Post by **Ilya Razmanov** » Wed Aug 02, 2006 3:17 pm

HaraldHeim wrote:You can fix it by dublicating the image on a new layer, adding a layer mask, drawing a gradient on the layer mask with the gradient tool and the adjusting the brightness of the new layer with the Levels tool.

Frankly, that's the rare case I'd disagree with you, at least to some degree

Unwanted signal in such an images rarely seem to be fully and properly approximated by simple linear gradient; normally, it's more complicated. So, while the technique you described will improve the quality to some degree, IMHO even dumb frequency filtering like highpass can often do better. Not to mention, it is likely to take less user efforts since frequency filtering don't care of gradient direction and stuff.

Just my personal opinion, nothing more