more details here: https://www.gimplearn.net/viewtopic.php ... 560#p21560

A while ago I thought of using addition mode to increase exposure of an image.
Today, I re-read the topic because someone tried to use it and replied on it then I thought the opposite (difference mode) should work to decrease the exposure (given you haven't completely destroyed details by super exposed).

Of course I tried it, and it works as expected.

So I wanted to share that as I haven't seen it talked about.

Screen mode to lighten and Multiply mode to darken have long been used for such things.

This is exactly the same as:

[list]
[*]Using "Curves", and dragging down the top right corner down.
[*]Using "Levels", and dragging the right handle of the "output" to the left
[*]

... with the very same bad results: your whites become gray.