I make my own dark frames to remove FPN rather than using the tools people have shared here, but I hope my question is still generally relevant and is somewhat apples to apples (even if perhaps McIntosh to Granny Smith).
It seems as though when subtracting the dark frames, a crucial decision is how strongly to apply them. So in Photoshop or After Effects for example, after putting the dark frame layer above the video layer and setting the blending mode to "subtract," you would adjust the dark frame's opacity to the value that removes the most FPN.
What I have noticed is that there is inevitably a compromise between FPN vertical lines in the lighter areas and the darker ones. As you reduce the opacity the lighter areas improve but the darker ones get worse. Obviously this is most problematic in high-contrast scenes.
My question: Is this a general characteristic of all dark frames?
It seems as though when subtracting the dark frames, a crucial decision is how strongly to apply them. So in Photoshop or After Effects for example, after putting the dark frame layer above the video layer and setting the blending mode to "subtract," you would adjust the dark frame's opacity to the value that removes the most FPN.
What I have noticed is that there is inevitably a compromise between FPN vertical lines in the lighter areas and the darker ones. As you reduce the opacity the lighter areas improve but the darker ones get worse. Obviously this is most problematic in high-contrast scenes.
My question: Is this a general characteristic of all dark frames?