Operation of an opaque projector

The opaque projector is a term little known and used in the French language. For many, this is the modern version of the magic lantern which is today called an episcope or epidiascope.

These two names designate two devices which differ in a few details. But, overall, these are devices that work the same way, that is, projecting bright light directly onto a non-transparent object. Light is reflected from the object and through a series of mirrors or prisms and a lens. This allows the user to magnify and transfer an image from a small opaque source to a larger area such as a whiteboard or canvas.

The magic lantern, a beautiful invention

Currently, if we are used touse the episcope or the epidiascope, the famous magic lantern has not yet lost its "magic" side. Indeed, it is the first projector in the world. He projects a light through glass slides with painted images. As printing evolved, manufacturers could produce glass slides with images printed rather than painted. These projectors worked by transmitting light through a transparent object. This transmitted light is known as transmitted light.

The episcope, an improved magic lantern

An episcope or episcopic projector is a device that uses the reflection of light to project an image onto a surface. The projector shines bright light on the opaque object. The light is directed by several mirrors or prisms towards the projection lens. But, the lens focus can be adjusted to change the image size.

The earliest episcopes were used to view postcard images, magazine images, advertising cards, and even images supplied by the projector manufacturer. An episcope, or opaque projector, can even be used to view small three-dimensional objects such as coins, leaves, or insects.

The epidiascope, an improved periscope

The episcope is a revolution compared to the magic lantern. But the epidiascope is even better, because it combines the ability to view transparent and opaque objects in one device. An epidiascope allows the user to view both slides and opaque objects.

The teachers and professors appreciate the ability to project pages of books, printed materials and photographs as well as slides or transparencies so that the entire audience can see the project object. However, as this technology is still analog, most modern classrooms are now equipped with a digital projector connected to a computer. However, epidiascopes are still considered devices that have advanced teaching.

The episcope and epidiascope used in art

Unlike an overhead projector or slide projector, an opaque projector (episcope or epidiascope) does not require you to transfer your image first to something transparent. It allows you to work directly from a photo. This ability made opaque projectors very popular with artists of the photorealism movement.

The artist can take a photo of what they would like to draw or paint on a larger area. As long as the photograph can fit in the opaque projector, the artist can enlarge it on canvas or other surface for tracing and painting. Some artists even use this method to reproduce images on a wall in order to paint a pattern.