Magic lantern slides dating of
A light is shone through the negative exposing the emulsion of the slide.
The slide is then processed using photographic developer, stop bath and fixer and then washed and dried.
Well before the novelty of the cinematographé had become established as cinema in the very early 20th century, lantern slides were widely used for public presentations.
The 1900 production by the Limelight Department of the Salvation Army, incorporated approximately 200 glass cinema slides to heighten the impact of the silent moving image footage.
The processing procedure is the same as that used in contact printing.
From the 1850s to the 1960s, most photographic slides were produced in monochrome, with colour added later in the form of chemical toning or dyes.
Brothers William and Frederick Langenheim in the US extended Niépce’s work, using a negative plate to print a positive image onto glass.
The results below indicate that the adhesive was probably a vegetable gum such as gum arabic.Cinema slides with photographic images were produced as duplicates from original or composite negatives.Contact printing uses a frame to hold the emulsions of the negative and slide together in close contact.Although the actual dyes used for an individual slide may be from almost any source, they have generally proven to be stable, especially compared with early colour photographic processes.As indicated in the graph below, research by the Glass, while fragile, is a stable substrate for the slide and for the image it supports.
The finished product ranged from text or simple line illustrations to sophisticated hand-coloured graphic designs.