Using GIMP to lighten shadows and darken highlights

I tend to use GIMP to edit my photos and one of the things I have found useful is a quick and easy way to lighten shadows and darken highlights.

For those that know some of the terminology and have used GIMP (I don’t pretend to be an expert so bear with me if I describe some of it incorrectly) what I do is use a desaturated, inverted duplicate layer set to “soft light” with reduced opacity.

In more detail:-

When editing your image in GIMP go to the menu option “Layer” then click on “Duplicate Layer”. The duplicate layer will now be active but if you do something else before continuing you will need to click on the duplicate layer in the layers toolbar. We now turn it into a black and white image by going to the menu “Colours” and then click on “Desaturate”. I then usually select “Luminosity” and click on “Ok”. When you have done this a few times you might want to try other options. You can also adjust brightness and contrast but remember that this is supposed to be a quick and easy way of making some improvements to the image. You can get clever with layers and layer masks but if you are into that sort of thing you are beyond this little guide.

Now we can invert the image by going to “Colours” and then “Invert”. We should now have a black and white negative of the original image.

Now “all” we have to do is blend this with the colour original by going to the “Layers” dockable window. Press Ctrl and L if you can’t find it. In this window change the Mode to “Soft Light” and reduce the opacity to give you the image you want. You can turn the duplicate layer on and off to see the effect by clicking the “eye” in the check box next to the duplicate layer in the dockable Layer window.

11 thoughts on “Using GIMP to lighten shadows and darken highlights”

  1. Thanks heaps – that works really well, and is quicker than some of the plugins I’ve used to get a similar result. So that’s what soft light is useful for :p

  2. Excellent how to – I am learning to work more with layers, and all those modes were mysterious – now I know what at least one of the extra modes can be used for 🙂 I was trying to dim the background light coming through one window while maintaining the overall color balance. Hard to do, and this helped a bit. I ended up just cropping the offending light source out 🙂

  3. I’ve never used wimp before and loaded it just for the purpose of fixing pics of groups of people of whom some were lost in the shade. This trick worked like a charm. Thanks.

  4. Hi, I’ve tried to do this, and probably went wrong somewhere, because I’m seeing the same effect as if I’ve turned down the brightness on the whole photo, i.e. not just the highlights?

      1. Thanks for your reply Paul. Yes I did. I find adjusting the brightness using the curve to be more effective in the end, though it is fiddly and tricky to master sometimes!

  5. Wow! Thank you so much, this tutorial just saved a bunch of my photos! I have little understanding of gimp so I had no idea where to start!

  6. Works like a charm. After applying the effect once, I flattened the layers and applied it a second time. Then adjusted darkness a bit higher and midrange a bit lower in levels. Applied a bit of unsharp mask, resized and saved. Results are every bit as good as the shadow highlight filter in photoshop express. Thanks for the tip.

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