GenealogyTips: Photograph Types

Photographic Types

Some of the photographic types you might encounter during your research include the following:

Albumen print: A type of photograph invented by Louis Desire Blanquart-Evrard of France in 1850 and in use through the early 20th century. An albumen print was produced on a thin piece of paper that was coated with albumen (egg whites) and salt, floated in silver nitrate, and then mounted on cardboard.

Ambrotype: A type of photograph patented in 1854, in which the pictures were produced on glass instead of a metal plate. Some considered them an inexpensive improvement over daguerreotypes because of the less reflective quality, but they lacked detail and tonal range.

Autochrome: A photographic plate patented in 1904 by Auguste and Louis Lumiere. In 1907 they began to commercially market the process, which used microscopic red-, green-, and blue-violet-dyed grains of potato starch mixed evenly and coated onto a sheet of glass. During exposure, a black-and-white emulsion flowed over this layer and caused the grains of potato starch on each plate to act as millions of tiny filters. The light-sensitive emulsion was then reverse-processed into a positive transparency that filtered the light passed through the emulsion to display the proper color of the starch grains, creating a mosaic of glowing dots on glass similar to the look of a pointillist painting.

Carbon print: A process patented by Joseph Wilson Swan in 1864 that offered a permanent print without grain, with a wide tonal range. Negatives were printed onto a tissue containing carbon and other pigments in a gelatin base made light sensitive by a bath of potassium bichromate. After processing, the image on the tissue could be transferred to a paper base and the backing of the tissue removed.

Collodion print: A photographic process similar to that used for ambrotypes that created a matte, glossy, or semigloss albumen-type print. Although these prints lack the yellowish cast found in the whites of albumen prints, they are difficult to distinguish from other 1890 -- 1910 silver prints and usually must be validated by a trained conservator.

Carte de visite: A type of photograph patented by photographer Andre Adolphe Disderi in 1854. It was a 2 1/2- X 4-inch-format paper print mounted on a card; collections were often bound together in photo albums.

Cyanotype: A process invented by Sir John Herschel in 1842 that created brilliant blue images with a matte surface. It was most popular around the turn of the 20th century. Cyanotypes are highly stable because the process used iron salts (rather than silver compounds) for the light-sensitive material; the same process was used to make architectural blueprints.

Daguerreotype: The first practical (albeit volatile, due to the lengthy exposure time required) form of photography, made public in August 1839. Daguerreotypes were made directly in the camera, not from a negative. The resulting “print” was always displayed behind glass, in a frame or a small folding case. The American Museum of Photography Web site maintains an online display of examples, as well as a detailed history of this process .

Dilute albumen print: An early variation of albumen print, with finer detail and tonality. Sometimes referred to as lightly albumenized print.

Glass plate negative: A type of photograph, made between 1848 and 1930.

Photogenic drawing: William Henry Fox Talbot created the photogenic drawing sometime around 1834, when he began making salt prints by putting lace, leaves, and other objects on light-sensitive paper he exposed to the sun.

Photogravure: A photomechanical process invented by Karl Klic in Austria in 1879, in which the finished prints were made in ink on a printing press. This method transferred the photographic image to a copper printing plate etched to retain ink in the areas corresponding to the blacks of the picture.

Platinum print: A matte surface type of photograph often highlighted with artistic chalk to give the photo a hand-drawn quality; typically taken between 1880 and 1930, they are the most permanent of all photographs.

Salt print: A process invented by William Henry Fox Talbot that produced a print with tones ranging from reddish brown to chestnut brown.

Silver print: A term used for a variety of processes using light-sensitive compounds such as silver chloride, silver bromide, and a mixture of the two, with tones that can mimic the silvery grays of platinum prints, the warm browns of albumen prints, or a range of other colors. It is estimated that more than a billion silver prints were processed in the 20th century. These prints require laboratory testing to verify that they are indeed silver prints.

Stereographic card: A photographic image that appears three-dimensional when viewed through a viewer, developed in the 1850s.

Talbotype: A photographic process invented by William Henry Fox Talbot in September 1840 in which a plain sheet of writing paper was dipped in potassium iodide and coated with a solution of silver nitrate to form silver iodide, dried, and floated on a mixture containing silver nitrate and gallic acid. After exposure, this paper negative was usually waxed for transparency and used to make salt prints. Also known as calbotype.

Tin type: The invention of Professor Hamilton Smith of Ohio, these photograph began as thin sheets of iron covered with a layer of black paint; first made in 1856 and used well into the 20th century.

Wet plate: A process invented in 1851 by Frederick Scott Archer of England that involved clear glass, coated with a very thin layer of iodized collodion, dipped in a silver solution in the darkroom to make it light sensitive, and then exposed in a camera before the chemicals had a chance to dry. It was used to produce negatives, but also used in a modified form to produce positives.

Woodburytype: The photomechanical process introduced in 1865 for producing prints in quantity in which a light-sensitive gelatin material was exposed to a negative, resulting in a three-dimensional relief map of the image that was then exposed to the highly applied pressure of a hydraulic press to make an impression in a block of lead. The resulting lead mold was used to make the prints, which had superb tonality and a slightly raised surface.

To further educate yourself about the history of photography so that you become more knowledgeable about those old photographs you’re now cataloging for the family, spend some time at The American Museum of Photography Web site. This site has an assortment of photo archives as well as A Primer of (photographic) Processes, which gives expanded definitions for the most common processes, as well as a wide assortment of links to related Web sites. While you’re there, you might also want to check out an article about how to best preserve photos. You can fine other preservation links at www.genealogytips.com, on the Chapter 11 page.