Although I doubt this is a useful bit or anything since probably someone else is covering this base on your team of restorators, I believe that this movie will be easier to fix the mild fading issue than most others for the basic fact that it provides hard captions as well as much of the footage being hard matted. Theoretically, one can make a white balance using the hard matte as an obvious black point and the captions as a white point.
I made a little test real fast to demonstrate my point (although please note, I forgot the title was “Return” not “Revenge” so minor whoops lol): http://screenshotcomparison.com/comparison/132337
I’m willing to bet this scan has a fade-corrected grade on top of it already. Look at how the dirt is blue-green instead of black - that is a side effect of stretching the red channel.
Fading doesn’t affect just the highlights or just the shadows in isolation, or one part of the frame more than another. It is a uniform reduction in contrast of the affected dye layer or layers, edge to edge, throughout the entire, exposed image. In prints the shift is more obvious in the blacks since that’s where the most dye is. Fortunately, the magenta layer - which has the most sharpness - is usually the last one to go, and just from personal experience with this stuff, if you see a little yellow and blue and green left, there is enough dye left to recover a color balance close to the original. It would be really interesting if the scanner supplied snippets of the film without fade correction whatsoever.
You can’t always assume that the frameline or hard matting was originally perfectly, solid black throughout or that the most transparent areas were perfectly clear. The highlights may have a slight tinge to them due to the processing. I’ve noticed this in LPP color from around the same time as G85. Depending on how each scene was timed, the darkest information could swing between slight green or brown or red. This makes it impossible to determine exactly what the original color balance was, so you will always have to settle with an approximation… the Australian Roadshow VHS is a good reference since it’s a transfer of an original theatrical print, but you still need to keep in mind that Roadshow’s telecine may affect the look of the film along with the fact that VHS has extremely limited chroma.
Digitization is always going to be an approximation, so it’s good to keep in mind that the scan’s color is going to be affected by the sensor (i.e. its dynamic range, SNR, color separation) the type of light source the scanner uses (diffuse or collimated) and even the monitor that you’re viewing the scan on. It’s also worth remembering that the film would have had a different color quality from screening to screening depending on the color temperature of the lamp and slight variations in color quality from print to print during the same print run.