How to apply a brightness gradient to a single layer?

[sebsy]

Hi folks,

First post here, so hello all

I'm very much a beginner with GIMP, and just learn by clicking on tools and playing with them to see what they do, and anything I cab't figure out I google and figure it out from there, but I'm having difficulty figuring out how to do something specific here.

I want to apply a gradient of brightness to just a single layer of an image, but for the life of me I can't. I know what to do in terms of applying the gradient, but I can only apply it to the whole image whilst I only want it to apply to one.

In searching for the answer, the best thing I found for my query was this https://graphicdesign.stackexchange.com/...brightness which actually seems to be an answer given by one of the moderators of this very forum, some 6 years ago (the part in yellow near the bottom).

Now, those steps are giving me the exact effect I am looking for, it's just I can't figure out how to apply the effect to a single layer. I have no issue applying other effects to a single layer, so perhaps this can't be done, though I suspect it is possible and I'm just missing something.

Any help would be much appreciated

[Ofnuts]

If the layer is fully opaque: duplicate your layer (this creates a layer with the same size and position), set the top copy to "Multiply" mode and create a white to black gradient on it. Now, if there are holes in the layer, the "Multiply" on the top layer applies to all layers below. This can be avoided by using a layer group. The groups acts like parentheses in math: the layers are combined as their mode indicates, and then the result is used like a single layer. See attached image for an example (check the Layers list).

   

Of course in all cases, you can further tweak the gradient using Brightness/Contrast, Levels, or Curves.

[sebsy]

Thanks for that, Ofnuts.

I can now apply the effect as intended to my images, much appreciated