If you want to darken an image in Gimp, there are a few different ways to go about it. The simplest way is to use the black and white adjustment layer. To do this, open the image you want to darken, and click on the black and white adjustment layer icon at the bottom of the Layers panel. To adjust the darkness, simply drag the slider left or right. You can also use a percentage value if you want to make more subtle changes. For example, if you want to make the image 50% darker, enter 50% into the slider value field and hit OK. If you want to make more drastic changes, you can also use the Levels adjustment layer. To do this, open the image you want to darken, and click on the Levels adjustment layer icon at the bottom of the Layers panel. To adjust the darkness, simply drag either of the two sliders left or right. You can also use a percentage value if you want to make more subtle changes. For example, if you want to make the image 50% darker, enter 50% into one of these fields and hit OK. ..
