Lably
Skip to content

Magic lantern

Type of image projector

  • 28 min read
  • 9 chapters
This is my magic lantern. It once belonged to my great grandfather. Magic Lantern
Andrei Niemimäki · CC BY-SA 2.0

Related on Lably

Through Lens, Leonardo da Vinci and Telescope

It was mostly developed in the 17th century and commonly used for entertainment purposes. It was increasingly used for education during the 19th century. Since the late 19th century, smaller versions were also mass-produced as toys. The magic lantern was in wide use from the 18th century until the mid-20th century when it was superseded by a compact version that could hold many 35 mm photographic slides: the slide projector.

Technology

Apparatus

The magic lantern used a concave mirror behind a light source to direct the light through a small rectangular sheet of glass—a "lantern slide" that bears the image—and onward into a lens at the front of the apparatus. The lens is adjusted to focus the plane of the slide at the distance of the projection screen, which can be simply a white wall, and it forms an enlarged image of the slide on the screen. Some lanterns, including those of Christiaan Huygens and Jan van Musschenbroek, used three lenses for the objective.

Biunial lanterns, with two objectives, became common during the 19th century and enabled a smooth and easy change of pictures. Stereopticons added more powerful light sources to optimize the projection of photographic slides.

Slides

Originally the pictures were hand painted on glass slides. Initially, figures were rendered with black paint but soon transparent colors were also used. Sometimes the painting was done on oiled paper. Usually black paint was used as a background to block superfluous light, so the figures could be projected without distracting borders or frames. Many slides were finished with a layer of transparent lacquer, but in a later period cover glasses were also used to protect the painted layer. Most handmade slides were mounted in wood frames with a round or square opening for the picture.

After 1820 the manufacturing of hand colored printed slides started, often making use of decalcomania transfers. Many manufactured slides were produced on strips of glass with several pictures on them and rimmed with a strip of glued paper.

The first photographic lantern slides, called hyalotypes, were invented by the German-born brothers Ernst Wilhelm (William) and Friedrich (Frederick) Langenheim in 1848 in Philadelphia and patented in 1850.

Light sources

Apart from sunlight, the only light sources available at the time of invention in the 17th century were candles and oil lamps, which were very inefficient and produced very dim projected images. The invention of the Argand lamp in the 1790s helped to make the images brighter. The invention of limelight in the 1820s made them even brighter, emitting about 6,000–8,000 lumens. The invention of the intensely bright electric arc lamp in the 1860s eliminated the need for combustible gases or hazardous chemicals, and eventually the incandescent electric lamp further improved safety and convenience, although not brightness.

Sign in to keep reading

8 more chapters are free with a Lably account.

More in Optical, navigation and astronomical