Overhead projector
Videos
An overhead projector, like a film or slide projector, uses light to project an enlarged image on a screen, allowing the view of a small document or picture to be shared with a large audience.
Overhead projector in operation during a classroom lesson
Mirror and lens
A worker loads documents into an Ozalid printer.
Opaque projector
Videos
The opaque projector, or episcope is a device which displays opaque materials by shining a bright lamp onto the object from above. The episcope must be distinguished from the diascope, which is a proj
Overhead projector
…non-reversed on the side opposite the focusing lens. A related invention for enlarging transparent images is the solar camera. The opaque projector, or episcope is a device which displays opaque materials by shining a bright lamp onto the object from above. The episcope must be distinguished from the diascope…
An episcope which was used in a University of Cambridge lecture hall in the late 1800s
Small episcope for home use
Henry Morton's projection as illustrated in François Moigno's L'art des projections (1872)