You see what you see.

I hear "The Hitch Hiker" in black and white. That's how imagination works: using our own material; our memories; the images in our head. That's closely related to our dreams ! My images of America in the Forties are - of course - black and white, belonging to my own private film stock in my brain archives: The 1940 Ford V 8 vehicle travelling along on the empty, endless Route 66, crossing dreary plains with desolated gas stations. And additionally my imagination is fed by dozens of films and by literature: Jack Kerouac, "On the Road", for example ... John Steinbeck ... Allan Ginsberg ... Guess "The Hitch Hiker" story on a wide screen, full colours -- it would be as ridiculous as Batman in the body of Michael Keaton or George Clooney.

Welles used to call his radio programmes " The Theatre of Imagination". That's what our brain is used for by radio: As a stage, an inner screen, a projection wall for our own fantasies stirred up and animated by the radio producer. Radio doesn't describe images - it's no "television without screen" - radio creates pictures, and they are different in each of us.
The technical wonders of digital TV make people fly, shrink, expand, explode and assemble again. But radio can do much more. In our tiny head, there is room enough for towns, landscapes, an ocean, a continent, the world, the outer space.

The output of radio is not fixed to the speakers at the wall - like the TV images need the physical screen, a rectangle of defined size. Radio is space. It's surrounding us. If the producer makes us listen, we are all ears.