Originally Posted by creeduk
Just wanted to say this indepth thread made me go back and look at FFT, I had come across this filter in the past but misunderstood it, I had done the classic FFT then IFFT and see no result (of course..doh!) now reading this and going through old threads I have got it working. I still find it easier to use HSL as it shows the issue up clearer I think, I had some good success carefully cloning the vertical and horizontal lines which got rid of small highlights in that area that caused problems in the images.
So thanks for thrashing this subject again, this time it stuck for me
Having revisited this issue I have a sneaking suspicion that despite (or because of) having both filters I may have been using the wrong one. Hence my HSL comment. The examples I have worked on show the same pattern on red channel using the rgb as is seen on the blue channel using HSL version. Slaps forehead repeatedly.