This reminds me of a clipping that I had from Calvin & Hobbes. Unfortunately
I lost it, so I don't remember the exact details, but it was something like
this:
Calvin: "Dad, why are all old photos in black and white?"
Dad: "Because all things were in black and white then."
Calvin: "REALLY???"
Dad: "Yes. The world only turned color in the 1800s."
Calvin: "WEIRD! Then why are old paintings in color?"
Dad: "Well, artists are eccentric, you know. Besides, they only turned into
color when everything else turned into color"
Calvin: "How about the old photos? Why didn't they turn into color photos?"
Dad: "They did, but they were color photos of black and white things.
Remember?"