|
|
Photography: Processes, Preservation, and Conservation
|
|
|
|
|
Major Crawford, Major Wright, Capt. St. George, and Capt. Bortingham of the Leith Fort Artillery (detail), ca. 1845. David Octavius Hill (Scottish, 1802–1870) and Robert Adamson (British, 1821–1848). Salted paper print from paper negative. The Rubel Collection, Purchase, Ann Tenenbaum and Thomas H. Lee and Lila Acheson Wallace Gifts, 1997 (1997.382.24).
|
Principal Photographic Processes, Arranged Chronologically
Daguerreotype. One-of-a-kind photograph on a highly polished, silver-plated sheet of copper, developed over mercury fumes. Characterized by a mirrorlike surface and astonishing detail. The first photographic process revealed to the public, in 1839; enjoyed widespread popularity in Europe, especially France, in the 1840s and in America through the 1850s. View a daguerreotype in the online collection.
Paper negative. The earliest type of negative, made of fine writing paper sensitized with silver salts, exposed in a camera, developed, and fixed; often waxed or treated for added transparency. Paper negatives generally impart a slightly fibrous texture to the print and exaggerate contrasts of light and dark. Invented by Henry Talbot in 1840 and modified by many photographers. Popular in Britain in the 1840s and in Europe from the late 1840s through the mid-1850s; rarely used in America. (Also called "calotype negative" or "Talbotype negative.") View a paper negative in this special exhibition preview.
Glass negative (wet plate). Glass plate coated with a layer of collodion (cellulose nitrate dissolved in ether) and sensitized in a solution of silver salts. Recorded far greater detail than paper negatives but required the photographer to coat the plate immediately before use and to develop the exposed negative before the collodion dried. Published in 1851; gained popularity throughout the 1850s, almost entirely replacing the paper negative by 1860. Remained in use until about 1880, when "dry plates" were introduced. (Also called "wet collodion" process.)
Salted paper print. Photograph on paper sensitized with silver salts, printed in sunlight in direct contact with a paper or (less frequently) glass negative and fixed. Characterized by a velvety matte surface; variations in chemistry yielded prints of varying hues. Used in Europe through the mid-1850s; used less frequently in America. View a salted paper print in the online collection.
Albumen silver print. Photograph on paper coated with egg white and sensitized with silver salts; most often used to print glass negatives. Characterized by a moderately shiny surface and fine detail. Commercially prepared albumen paper was available beginning in the mid-1850s and remained popular through the 1890s. The most common photographic printing process of the nineteenth century. View an albumen silver print in the online collection.
Glass negative (dry plate). Commercially prepared glass plate coated with a gelatin binder and sensitized with silver salts. Far more convenient than the wet plate, which it rapidly replaced in the 1880s. Panchromatic dry plates, sensitive to all colors of the spectrum, introduced in 1906. Commonly used into the 1920s; available today but used only for specialized applications.
Platinum print. Photograph on paper sensitized with a solution of iron and platinum salts; processed to yield a platinum image. Usually printed in direct contact with a negative. Characterized by permanency, wide tonal range with subtle gradations, and matte surface. Invented in 1873; gained popularity in the late 1880s. Scarcity of platinum during World War I led to the substitution of silver-platinum and palladium papers. Undergoing revival since the 1970s among artists using commercial and hand-coated platinum papers. View a platinum print in the online collection.
Photogravure. Photographic image printed in ink from an etched copper plate. Characterized by rich inky blacks; the "whites" are the bare paper. One of the finest means for reproducing a photograph in large numbers. Popular with artists at the turn of the twentieth century.
Gum dichromate print. Photograph on paper coated with a sensitized gum solution containing pigment; printed in sunlight in direct contact with a negative and developed in water. Characterized by broad tones, high contrast, and lack of detail, gum prints often resemble paintings, pastels, or charcoal drawings. Popular among Pictorialist photographers of the 1890s and 1900s; rarely used today. (Also called "gum bichromate print.") View a gum dichromate print in this special exhibition preview.
Carbon transfer print. Photograph made by contact printing a carbon tissue (photosensitized, pigmented gelatin on thin paper), transferring it to paper, and developing it in water. Characterized by extreme permanence, fine grain, and continuous tone. Carbon tissues were commercially available beginning in 1864, with fifteen colors available by 1893, mostly shades of reddish brown, eggplant, and black; used widely for art reproduction and commercial applications.
Film negative. Similar to the glass negative, captures an image with light-sensitive silver salts in a gelatin binder. Uses a plastic support that, unlike glass, is lightweight, nonbreakable, flexible, and can be rolled, so that many images can be made on one length of film. Flexible negative supports were introduced by Eastman Kodak Company in the late 1880s. The early support, cellulose nitrate, was generally replaced by varieties of cellulose acetate and polyester beginning in the 1930s. If not stored properly, nitrates and cellulose acetates have inherent stability problems.
Greek Revival Doorway, New Orleans, Louisiana, 1935. Walker Evans (American, 1903–1975). Left: film negative suffering from deterioration; right: gelatin silver print from the negative after restoration by Chicago Albumen Works. Walker Evans Archive, 1994 (1994.258.648).
Gelatin silver print. Photograph on paper or plasticized paper coated with an emulsion of light-sensitive silver salts suspended in gelatin, printed out or developed out, and fixed. Came into general use in the 1880s; the developed variety remains the standard black-and-white photographic process. View a gelatin silver print in the online collection.
Carbro print. Exceptionally permanent full-color photographic image made by transferring yellow, cyan, and magenta layers of pigment to a final receiving sheet. Used primarily for portraiture and in advertising from the 1920s to the 1950s. View a carbro print in this special exhibition preview.
Chromogenic print. The most common type of color photograph, printed from a chromogenic color negative; consists of dyes within gelatin layers on a plastic-coated paper base. Subject to fading and color shifts in dark storage and on exhibition. Developed in the 1940s as an outgrowth of chromogenic color transparencies (Kodachrome, invented in 1935). Used by amateurs and artists alike. (Also called "C-print" or referred to by various brand names.) View a chromogenic print in the online collection.
Dye transfer print. Color photograph made by transferring to paper yellow, cyan, and magenta dyes from color separations of an image. Process permits precise control of image color. Used for fine art or advertising prints from the late 1940s to the early 1990s.
Dye diffusion transfer print (Polaroid). Self-developing color photograph. The complex process, first described by Edwin Land in 1947, has been popular among amateurs and artists since the early 1960s. (Also called "instant color print" or referred to by the product names "Polacolor" or "SX-70.") View a dye diffusion transfer print in the online collection.
Silver dye bleach print. Dye image in gelatin on a plastic or plastic-coated paper base, created from a positive transparency rather than a negative. Until recently, available only with a highly glossy surface. More stable than chromogenic prints. Introduced in 1963. (Also referred to by the old brand name "Cibachrome.")
Ink jet print. Photograph produced by a computer printer from a digital file using water-based dyes or pigments on paper or other support. (Also referred to by the brand names "Iris print" or "Giclée print.) View an ink jet print in this special exhibition preview.
BACK TO TOP
Other Terms
Contact print. Print made by placing photographic paper in direct contact with the negative in a glass frame and exposing it to light without the aid of an enlarger; negative and print are thus the same size. Nearly all photographs made prior to the 1880s were contact printed.
Printed-out print. Photographic print (whether salted paper, albumen silver, gelatin silver, or other) that darkens gradually during long exposure to light through a negative; the silver salts are transformed into metallic silver particles by the action of light alone without chemical developers. Most nineteenth-century and some early-twentieth-century photographs were "printed out" in sunlight. Generally warm in color unless toned.
Developed-out print. Photographic print made by brief exposure to light through a negative to create a latent image that is then transformed into metallic silver and made visible by chemical development. Briefly used in the 1850s for commercial photographic publishing; reintroduced in the late nineteenth century and dominant in the twentieth. Generally cool or neutral in color unless toned. All black-and-white negatives are similarly developed.
Toning. Chemical treatment of a photographic print during or after fixing. Generally used to alter the color of the print for aesthetic reasons or to increase the permanence of the image. Includes gold or platinum toning of printed-out images and sulfur or selenium toning of developed-out images. View a toned gelatin silver print in this special exhibition preview.
Vintage print. Print made close to the time of the negative, which most often represents the artist's original intention. There is no hard-and-fast rule regarding how soon after the negative a print must be made in order to be considered vintage; what is more important is that the materials, technique, and ideas remain consistent with the artist's original conception.
BACK TO TOP
|
Back to main page for this exhibition
Back to expanded page for this exhibition
