Re: Hypothetical question
Many years ago this came up in Victor Blackman's Cameravaria. You're going to have to get someone to search the archives if you want to find the article, but it was probably 1963-67.
He'd met someone (can't recall whom) who claimed that the different wavelengths of light affected the grains in film differently, and that it was possible to reconstitute the colours - using some unrevealed process. VB did put him to the test, and got back a colour print with amazingly a yellow cast in the foreground caused by an out of image yellow object that VB knew was there but the other fellow didn't.
I find this as hard to believe as VB did, but it's the nearest I've ever come to hearing that it's possible.
Stephen
If a thing's worth doing, it's worth doing to excess.