The saga of the GIMP tale.
5. RC on your picture, and go to Image --> Colors --> Desaturate. This will take all of the color out of the second layer.
6. Ctrl-C will copy that layer.
7. Go back to the layer box RC on the copy layer, and choose “Add Layer Mask”, this will bring up another box, choose to make it a white layer with full opacity. (There are only 3 choices, so this is not that hard. Just try it.)
8. Be sure that the background copy is the layer that is chosen, and go back to you picture box. RC and go to Edit --> Paste.
This puts your copy that you made in step 6 on top of everything else.
9. RC on your picture go to Layers --> Anchor Layer.
All of these steps won't take you very long at all. There is nothing subjective, it is just by the numbers so far.
You will notice that in your layers box you can click on both of the items in your background copy layer. Be sure that your mask is selected by clicking on it. (When you anchor your pasting in step 9, it should go into the mask part of the layer.
10. Go to your picture box, RC select Image --> Colors --> Invert for the layer mask.
11. RC again on the picture and go to Filters --> Blur --> Gaussian Blur IIR, this will bring up a box that lets you tell it how much of a blur you want. Make it a 25 Radius.
12. Go to the layers box. Right below the tabs where you can choose Layer/Channel/Paths there is a title of “Mode” select that drop down and choose “Screen”
You will notice that there is now some benefit already. Now there is some more stuff that we can do:
13. Click on the copy layer itself in the layer window, not the mask.
14. Go to the picture box and select Image --> Colors --> Levels
15. This brings up a funky looking graph that isn't much good for anything except making your pictures look good. Adjust the sliders to increase the white levels in the image.
Sometimes pictures are so bad that you need to start over. If that happens I just switch it to a black and white, and then it can be brightened up by using the Image --> Colors --> Brightness and Contrast selection. Many times those will be the best photos you can use.
There are a lot of steps in this task, but the thing to remember is that nothing really required any judgement until you got to the last 2 or 3 steps. Just like baking a cake, the recipe just needs to be followed.