"NY" wrote:

"John Doe" wrote

but white text on a dark background is better for reading.

Damn! Printed books have had it the wrong way round for all those
centuries

Joking apart, I know what you mean: when I first saw black-on-white in
GEM and the Apple II, having been used to white-on-black (or even
amber- or green-on-black) VDUs, I thought that GEM/Apple looked
hideous.

Paper doesn't emit light, it reflects light. So reading a book is not
like reading on the surface of a lightbulb. Making paper white is/was
easier and consumed much less ink than making the pages of a book
black/dark. Chalkboards are commonly dark using a white piece of chalk.

Less ambient light helps focus, as long as the view of interest is
clear. That's why movie theaters are dark.