The optical process
- The Camera Obscura (dark room) had existed for at least 400 years; the basic principles were known to Aristotle (384-322 B.C.), who used a pinhole to project the crescent image of a partial eclipse.
- A pinhole on one wall projected an image of the outside world onto the opposite wall.
- Leonardo da Vinci sketched it in 1519 as a drawing aid.
- The pioneers of photography added a lens as a way to gather and intensify light.