Photographic film is sometimes referred to as a "Negative" because it stores a reversed image (dark areas are light and vice versa) of the subject. Film is either configured as a strip or sheet of transparent plastic, base coated on one side with a gelatin emulsion. This emulsion contains light-sensitive silver halide crystals, the properties of which determine the film’s sensitivity, contrast and resolution. 

The first transparent plastic roll film appeared in 1889, a few years after George Eastman produced the first flexible (paper-base) photographic roll. In 1908 that Kodak introduced cellulose acetate or "safety film" which replaced the highly flammable nitrate film. By this time, film had become cheaper and better quality and replaced glass slides as a mass market photography medium. 

By contrast, reversal film is a type of photographic film that produces a positive image (not reversed) on a transparent base. The film is processed to produce transparencies. A slide is a specially mounted individual transparency (usually 35mm, but other sizes exist) intended for projection on to a screen using a projector.

Our scanning bureau can handle almost any type of film or transparency. We have the equipment and expertise to faithfully convert images from these formats to a more accessible and future-proof digital format.