How B&W pictures turned into color images in the 1930's

~ later version recorded in 1938 ~
(Calvin and Hobbes by Bill Watterson, © Universal Press Syndicate)

It isn't easy to teach children the history of photography and explain why the world used to be only black and white photography.

For those of you who want to educate the youngsters in the real history of photography, here is the dialogue:

CALVIN: Dad, how come old photographs are always black and white? Didn't they have color film back then?
CALVIN'S DAD: Sure they did. In fact, those old photographs are in color. It's just the world was black and white then.
CALVIN: Really?
CALVIN'S DAD: Yep. The world didn't turn color until sometime in the 1930s, and it was pretty grainy color for a while, too.
CALVIN: That's really weird.
CALVIN'S DAD: Well, truth is stranger than fiction.
CALVIN: But then why are old paintings in color?! If the world was black and white, wouldn't artists have painted it that way?
CALVIN'S DAD: Not necessarily, a lot of great artists were insane.
CALVIN: But ... but how could they have painted in color anyway? Wouldn't their paints have been shades of gray back then?
CALVIN'S DAD: Of course, but they turned colors like everything else in the '30s.
CALVIN: So why didn't old black and white photos turn color too?
CALVIN'S DAD: Because they were color pictures of black and white, remember?

(CUT TO: EXT. Tree limb, Calvin talking with Hobbes)

CALVIN: The world is a complicated place, Hobbes.
HOBBES: Whenever it seems that way, I take a nap in a tree and wait for dinner.

~ original version from before 1930 ~
(Calvin and Hobbes by Bill Watterson, © Universal Press Syndicate)