I've been curious about average film histograms for color correction.

Something like getting the color histogram from every frame of a target, and averaging them together. Then doing the same for a reference.

Then running a two pass color correction similar to encoding, where the first pass goes through and finds the best way to compress the chroma to "fit" the reference, and the second pass tightens that a little and actually does the color correction shift on each frame.

Not sure if that would work, but theoretically seems like a good way to do a preparation color correction to remove any tinting done across the whole film.