Duplitized film was a type of motion picture print film stock used for some two-color

natural color Natural color was a term used in the beginning of film and later on in the 1920s, and early 1930s as a color film process that actually filmed color images, rather than a color tinted or colorized movie. The first natural color processes were in t ...

processes. It was introduced by

Eastman Kodak The Eastman Kodak Company (referred to simply as Kodak ) is an American public company that produces various products related to its historic basis in analogue photography. The company is headquartered in Rochester, New York, and is incorpor ...

around 1913. The stock was of standard gauge and thickness, but it had a

photographic emulsion Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of g ...

coated on both sides of the

film base A film base is a transparent substrate which acts as a support medium for the photosensitive emulsion that lies atop it. Despite the numerous layers and coatings associated with the emulsion layer, the base generally accounts for the vast majority ...

instead of on one surface only. In color film processes such as

Cinecolor Cinecolor was an early subtractive color-model two-color motion picture process that was based upon the Prizma system of the 1910s and 1920s and the Multicolor system of the late 1920s and the 1930s. It was developed by William T. Crispinel and ...

and

Prizma The Prizma Color system was a color motion picture process, invented in 1913 by William Van Doren Kelley and Charles Raleigh. Initially, it was a two-color additive color system, similar to its predecessor, Kinemacolor. However, Kelley eventual ...

, two

black-and-white Black-and-white (B&W or B/W) images combine black and white in a continuous spectrum, producing a range of shades of grey. Media The history of various visual media began with black and white, and as technology improved, altered to color. ...

negatives photographed through red and blue-green

filters Filter, filtering or filters may refer to: Science and technology Computing * Filter (higher-order function), in functional programming * Filter (software), a computer program to process a data stream * Filter (video), a software component tha ...

, or by an equivalent

bipack In cinematography, bipacking, or a bipack, is the process of loading two reels of film into a camera, so that they both pass through the camera gate together. It was used both for in-camera effects (effects that are nowadays mainly achieved via o ...

method, were photographically printed onto opposite sides of the duplitized film. Because its emulsion was sensitive only to blue light, a temporary yellow dye incorporated into the film prevented each printing light from also exposing the emulsion on the other side. The exposed film was developed like ordinary black-and-white film, producing a series of black-and-white silver images on each side. These were then chemically converted into single-color images of a color roughly

complementary A complement is something that completes something else. Complement may refer specifically to: The arts * Complement (music), an interval that, when added to another, spans an octave ** Aggregate complementation, the separation of pitch-class ...

to that being used for the images on the other side and to the color of the camera filter used when filming them. The resulting superimposed pairs of transparent single-color images, projected onto a screen or viewed directly, could reproduce a limited but useful and sometimes very pleasing range of color. It was mainly in the specifics of the chemistry, apparatus and procedures used to convert the silver images into color-toned ones that the several commercial processes based on the use of duplitized film differed significantly. Large sheets of duplitized film were sometimes used for medical

X-ray photography Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeut ...

. The double emulsion increased the overall sensitivity of the film, reducing the X-ray exposure required. Duplitized film of any kind was not suitable for ordinary camera use, due to the loss of image quality that would result from the light becoming diffused as it passed through the several layers, but with X-ray shadows that was not a problem.

See also