# Photoshop/GIMP question

**URL:** <https://boards.straightdope.com/t/photoshop-gimp-question/645050>\
**Category:** Factual Questions\
**Created:** [December 24, 2012, 8:59pm UTC](https://boards.straightdope.com/t/photoshop-gimp-question/645050 "2012-12-24T20:59:44Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![cainxinth](https://avatars.discourse-cdn.com/v4/letter/c/7bcc69/32.png) [@cainxinth](https://boards.straightdope.com/u/cainxinth)\
**Post date:** [December 24, 2012, 8:59pm UTC](https://boards.straightdope.com/t/photoshop-gimp-question/645050/1 "2012-12-24T20:59:44Z")

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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?

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**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\
**Post date:** [December 24, 2012, 11:05pm UTC](https://boards.straightdope.com/t/photoshop-gimp-question/645050/2 "2012-12-24T23:05:13Z")

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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.

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**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\
**Post date:** [December 25, 2012, 12:05am UTC](https://boards.straightdope.com/t/photoshop-gimp-question/645050/3 "2012-12-25T00:05:46Z")

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Make sure you are working in the graphic program’s native format. In the case of Photoshop, a .psd file.

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**Author:** ![cainxinth](https://avatars.discourse-cdn.com/v4/letter/c/7bcc69/32.png) [@cainxinth](https://boards.straightdope.com/u/cainxinth)\
**Post date:** [December 25, 2012, 12:54am UTC](https://boards.straightdope.com/t/photoshop-gimp-question/645050/4 "2012-12-25T00:54:40Z")

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> [@NitroPress](#):
>
> 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.)

Thanks, that helps.

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**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\
**Post date:** [December 25, 2012, 12:57am UTC](https://boards.straightdope.com/t/photoshop-gimp-question/645050/5 "2012-12-25T00:57:19Z")

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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.)

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**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\
**Post date:** [December 25, 2012, 3:24am UTC](https://boards.straightdope.com/t/photoshop-gimp-question/645050/6 "2012-12-25T03:24:16Z")

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> [@Duckster](#):
>
> Make sure you are working in the graphic program’s native format. In the case of Photoshop, a .psd file.

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.