I use the
Histogram manipulate as a proof-of-concept guide. Depending on how that goes, one could seond-guess what they might've done to put the film into it's present state. If successful, that can be used as a guide for
Curves to fine tune it, like with the too-strong low-end green.
Using that approach for
Curves, I first checked for areas of crush and blown primaries (RGB). These pictures had some of that from
Red being pushed down for their bluish result. The first thing I did was to lock-down the picture to the 16-235 range. In this case, the lowest value of each
R-G-B was moved up to 16 (shown as "0,16). The highest value was moved down to 235 in each, too (shown as "255,235). Note that I use the minimum number of points to approximate the
Histogram's curve, just o guide the curve. Trying to "micro-manage" it will generate unwanted artifact-colors in odd places.
Then I looked around to see what needed tweaking (like the strong, low-end green) and other wrong coloring, of which I found. Normally, that's where I stop. But here, I wanted to expand a little of the near bottom of the spectrum to show some of the detail in the shadows that had been pushed together. (Since my monitor is not calibrated, I don't know if this last setting was a valid adjustment. It seems to look a little better on my end.) I didn't want to adjust each
R-G-B individually, so I used the
RGB-curve, which applies one setting equally to all. Here are those settings . .
. . and here is the resulting comparison (open in a new tab for full-sized) . .
I miss the loss of the super-green Peter Pan costume. Oh, well, that's the trade-offs. So, correction is do-able. Probably the real next step is getting a hold of some original source(s) to guide what colors should be.
If
Avisynth fails to have a filter to handle the settings data (I've looked and can't find one that just takes the numbers and runs), there is a really good
VirtualDub filter that can do it (and it's interactive, too!). I'll look for where and then come back with a link.