ww12345 said:

I'd be interested to see if you could make some sense out of my color correction software ...

What I do in the paint program looks like it falls under the main category
MASTER (PFC picture 1)

My settings (shown here from an older posting) are
Low .. Gamma .. High .. Midtones

Your MASTER :: HISTOGRAM (PFC picture 4) has my Histogram settings of Low and High, for each channel R-G-B. Normally, I would set these to stretch out the ends of the shrunken spectrum due to fading. In this case, each R-G-B channel already has been expanded in the capture. So Low will remain at it's default of 0 and High at it's default. In the paint program, the High maximum is hard-wired to 255. In PFClean, it is set to the relative value of 1.0 to allow for more than 8-bit range (0 to 255). When needed to convert my numbers to yours, divide mine by the maximum of 255. It's that simple.

Your MASTER :: COLOUR (PFC picture 2) has my Histogram setting of Gamma for each channel R-G-B. This adjusts the low end in proportion to the rest of the spectrum, with the higher end least unaffected. This mostly adjusts the shadows for more visibility while changing R-G-B color strength that moves into the mid area. From the tick-marks, it looks like my numbers, default = 1.0, minimum = 0, and maximum = 5, may correspond directly to yours.

Unfortunately, I don't see anything here that looks like Histogram's Midtones, unless there is a screen not posted here that produces it's characteristic "S" curves. Histogram has default = 0, minimum = -50, and maximum = 50. If need be, I can just post my Histogram graph with Midtones only for you to recreate the shape in your MASTER :: CURVES for each channel R-G-B.

That's all I use ... at this point. From the PFClean demo video, you could try the auto-color-correction(s) to determine how useful it is. As much as you can, go for general manual settings and/or automatic settings that do the acceptable job (because this is a BIG job).