Flat field correction

[Donatzsky (Nis Donatzsky)]

See here:

How to balance exposure with external raster mask?

A great thank you Todd, actually that works using divide, I misunderstood at first! And I am surprised how well that works, even though I have not been using a tripod, so the background does not align perfectly, the overall light distribution is much better. What I did different is that I had just used the tone curve and pulled up the left hand side and pulled down the right side to invert the background image, as I was not sure about the exact parameters using negadoctor. For example, this is …