Boxes of film for colour slides, c 1960.
© National Media Museum / Science & Society Picture Library
Boxes of Agfacolor and Kodachrome II film for colour transparencies. The first colour slide film was Kodachrome, introduced by Kodak in 1936. Slides are positives, images which have the same tonal values and colours as the original scene. Transparencies are viewed by transmitting light through them in a projector onto a screen, or on top of a lightbox, whereas with print film the negatives taken by the camera need to be made into positive prints. Today a variety of different slide films are available, for colour and also black and white photography. Improvements in technology relating to the finenes of the grain in the emulsion enable images of outstanding sharpnes and detail rendition to be taken using modern transparency films.