Black and White

From Ask Calvin's Dad

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