Hello RJH. I think this is your first visit so welcome. If you are using Photoshop it is very easy. Click on Image>Adjust>Levels. You will now see a Histrogram (like the outline of a mountain) and underneath it are three pointers. Click and drag to the left on the righ-hand pointer a little bit at a time which will brighten up your image. Dragging the left-hand pointer to the right will darken it, and you can use the middle pointer to try and recover any detail that is blocked out. I find that Levels works best by leaving the left and right pointers at the bottom edges if the "mountain". Hope it works for you. It might look something like the attached modification.