and we have a winner!
That game.... I don't know if there was a manual I didn't have, or a clue that I missed, but you had to develop photographs in that game with a precise formula. Well, I couldn't find how anywhere in the game, so I pulled an encyclopedia (no internet at the time), found the exact formula needed to develop photos, and boom, I solved the puzzle! One of the most satisfying (and frustrating) experiences ever!