--The Reverend Jim said: "Then I only need to find out the original emulsion
before I take on Murphy."

I wonder if even knowing that would eliminate Murphy, as there are
additional variables thrown in by the developers used, being able to
accurately identify which emulsion you're looking at, whether or not you
even have the negatives available. When time has moved forward, and people
are looking at faded colour photos for clues about paint, things probably
won't be much better.

sign me, a lighter pail of shade