I want to match the dark area on the bottom right of my image to the bright area on the top left. I have tried equalizing and working with levels to no avail. Thanks
I am not sure if understand the question correctly but I will give it a try.
I assume that your image has a diagonal brightness inequality, from top-left to bottom-right.
Depending on how uniform this inequality is, you can try the following technique:
If these don't answer your question, please clarify it.