The Magic Lantern - Example of a Lantern Slide aka Hyalotype

Produced to be viewed with a projector, lantern slides were both popular home entertainment and an accompaniment to speakers on the lecture circuit. The practice of projecting images from glass plates began centuries before the invention of photography. However, in the 1840s, Philadelphia daguerreotypists, William and Frederick Langenheim, began experimenting with The Magic Lantern as an apparatus for displaying their photographic images. The Langenheims were able to create a transparent positive image, suitable for projection. The brothers patented their invention in 1850 and called it a Hyalotype (hyalo is the Greek word for glass). The following year they received a medal at the Crystal Palace Exposition in London.