Originally Posted by LonK
Actually 4 layers: Background, low freq, high freq, color. I find separating the color aids in working on the other two as I only have to deal with luminosity. Of course, in this case, the color is pretty monotonous and straight toning would work just fine.
On the original separation, I used a very high GB radius. This essentially put most of the damage on the HF layer. Using quickmask, I loosely selected only the stained part and used surface blur to pretty much wipe it out. Then I added weak film grain to get back some texture. On the LF layer I did the macro D&B to correct the luminosity and contouring. For my quickie demo (10 minutes), I just used the dodge/burn tools right on the layer. To go totally non-destructive, a clipped grey layer works just as well.
That's incredible restoration work. I've downloaded this photo & I would like to learn this process. I've done a search for "frequency separation" & "d&b" but am unable to find any specific instructions on the whole process. What is frequency separation, what is the theory of it & what are it's uses. I'm familiar with d&b on a 50% gray layer (white brush/black brush, low opacity) which is how I do most if not all my d&b. I use the HP filter & GB filter when making certain masks & for sharpening. I've just learned that the HP filter & the GB filter when set at the same radius will sort of cancel each other & change nothing. Kind of like Congress.
Would you mind sharing the step by step process. (If so, please be specific). If you've written a book on this, please tell me where I can buy it.