When I’m working on an image there are sometimes defects that I can only see by lowering the brightness way down. Is there an easier way to expose those flaws?
Not really. Ramming brightness or contrast to extremes is a good way to reveal some kinds of image flaws.
If you’re using a late enough version of Photoshop, you can use an adjustment layer to apply the extreme correction and not damage the image layer - just toggle the adjustment layer on and off as you work to help locate and fix the flaws. (Remember to re-generate the adjustment layer from time to time to include your fixes.)
Not sure if GIMP has any equivalent feature.
Make sure you are working in the graphic program’s native format. In the case of Photoshop, a .psd file.
Thanks, that helps.
In GIMP, Colors–>Auto–>Equalize will apply histogram equalization, which is a standard approach toward OP’s objective (though normally thought of as enhancing low-contrast detail, rather than enhancing “flaws.”)
(Adaptive histogram equalization, introduced by Stephen Pizer, is even better, but AFAIK, unavailable for Photoshop or GIMP.)
It makes little difference. Photoshop does not modify the open file until it’s saved, and then it writes an export form without modifying the open image. You can work in, say, JPEG and only the state of the image at the time of save is preserved. (You do not get a JPEG compression loss of the work file every time you save, only when you re-open the saved file.) Of course, any file where quality is important should be maintained in one of the lossless formats, with PSD being superior to all others.