Exactly what it says, honest.
Make any sort of print (including mini-lab from film).
Make a colour Xerox of it (ideally flopped -- or flop the original -- because the transfer will of course be reversed left for right). Many public libraries have colour Xerox machines nowadays.
Soak the colour Xerox in solvent.
Burnish down onto water-colour paper (or anything else, really) with the back of a spoon.