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Holography Glossary


  • Callier effect - contrast effect in photographic printing caused by the scattering of directional light from an enlarger condenser system. The negative highlights are of high density and scatter more light with little or no scattering from negative shadow areas, which are of low density. This gives a print higher contrast than a contact print.
  • Calotype process - first negative/positive process, invented by W.H. Fox Talbot in 1839. Paper was coated with silver iodide and a solution of silver nitrate and gallic acid. After exposure the paper was developed in a silver nitrate solution.
  • Camera lucida - lens and prism system through which a virtual image was seen, apparently appearing on the surface of the drawing paper.
  • Camera obscura - origin of the present day camera. In its simplest form it consisted of a darkened room with a small hole in one wall. Light rays could pass through the hole to transmit on to a screen, and inverted image of the scene outside. It was first mentioned by Aristotle in the 4th Century B.C. and developed through the centuries as an aid to drawing.
  • Canada balsam - liquid resin with a refractive index similar to glass. It is used for bonding elements in compound lenses.
  • Candid pictures - unposed pictures of people and animals, often taken without the subject's knowledge. These usually appear more natural and relaxed than posed pictures.
  • Carbon process - contact printing process, introduced in 1866, using tissue coated with pigmented gelatin. The paper was sensitized in potassium bichromate and contact printed behind a negative in sunlight.
  • Carbon tetrachloride - liquid used for removing grease and finger prints from negatives.
  • Carbro process - early color print process using an adaptation of the carbon printing process.
  • Carte-de-visite - portrait photograph on a mount about the size of a postcard. Introduced in 1854, carte-de-visite became a social craze in many countries during the 1860s.
  • Cast - overall bias toward one color in a color photograph.
  • Caustic potash - high alkaline used in high contrast developing solutions to promote vigorous development. Highly corrosive and poisonous.
  • Chemical vapor - method of exposing negatives in a closed container to a small amount of mercury of sulfur dioxide. After approximately 24 hours the film is developed normally. It produces interesting yet very inconsistent results.
  • Chiaroscuro - light and shade effect. The way in which objects can be emphasized by patches of light, or obscured by shadow.
  • Chlorhydroquinone - developing agent contained in warm tone developers.
  • Chloride paper - printing paper with a silver chloride emulsion. Much less sensitive than bromide paper. Mainly used for contact printing. *Chromogenic development - process in which the oxidation products of development combine with color couplers to form dyes during processing.
  • Chlorobromide paper - photographic paper coated with an emulsion made up of both silver chloride and silver bromide. Used for producing enlargements with a warm, slightly brownish-black image, especially if processed in a warm tone developer.*Chronocyclograph - photograph used for the analysis of complex cyclic movements.
  • Chlorquinol - alternate term for chlorhydroquinone.
  • Chrome alum - alternative term for potassium chromium sulfate.
  • CIE standard - system of standards adopted by the Commission Internationale de I'Eclairage, allowing accurate descriptions of colors.
  • Clayden effect - desensitizing of an emulsion by means of exposure to a strong, brief flash of light.
  • Clearing agent - processing solution used to remove stains or to cancel out the effect of chemicals left on the sensitive material left from previous stages in the process.
  • Cliche-verre - designs painted on glass in varnish or oil paint, or scratched into the emulsion of a fogged and processed plate using an etching needle. The results are then printed or enlarged on photographic printing paper.
  • Collage - composition employing various different materials combined with original artwork attached to some type of backing.
  • Collodion - soluble gun-cotton, dissolved in a mixture of ether and alcohol.
  • Collodion process - also known as "wet collodion" was invented by Frederick Scott Archer in 1851-52. It was a great improvement over the earlier calotype process because because of the large increase in speed gained by exposing the plate while still "wet", but it had the disadvantage of requiring bulky equipment.
  • Color toning - system of changing the color of a black and white photograph by converting black metallic silver into a colored compound.
  • Combination printing - producing a composite image by printing more than one negative on a single sheet of paper.
  • Compensating positive - image on translucent material that can be printed together with the negative of the same image. When combined the result makes printing contrasty negatives easier.
  • Constructivism - art movement that begun in Russia c. 1913. Characterized by the use of everyday materials in abstract compositions.
  • Contact screen - type of half-tone screen in which the dots consist of slightly unsharp halos. Used to make half-tone images.
  • Contour film - special print film producing a equidensity line image from a continuous tone negative or print.
  • Contre-jour - backlighting. A photograph taken with the camera pointed directly at the light source.
  • Copper chloride - chemical contained in certain bleaches, toners, intensifiers, and reducers.
  • Copper sulfate - chemical contained in certain bleaches, toners, intensifiers, and reducers.
  • Copper toning - chemical process used for toning monochrome prints.
  • Coving - plain curved background which has no edges, corners or folds and gives the impression of infinity.
  • Cubism - early twentieth century European art movement characterized by the rendering of forms as simplified planes, lines and geometric shapes.