PERFECT PHOTO PIXELS

ALL ABOUT PHOTOGRAPHY BY DOMINIQUE JAMES

The essential cutting-edge photo printing techniques of yore

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BY DOMINIQUE JAMES

Do you know what are some of the most important pre-digital photo printing techniques? Can you name a few of these photo printing methods? Or, how about describing the difference and similarities between an ambrotype and a woodburytype? Do you even know what they are?

Before the advent of digital photo printing processes, photo prints were created through various, and oftentimes time-consuming, elaborate, laborious means, based on the known and prevailing high technology of the times. And yes, including ambrotype and woodburytype processess. Long before you are able to print photos by simply and conveniently feeding an inkjet printer with a photo paper and pressing a button, you might be surprised to find out how hard and difficult it used to be in photographically printing images.

During my recent excursion to San Francisco’s Museum of Modern Art (MoMA), I had the pleasure of viewing the museum’s permanent collection of precious photo prints on exhibit. Entitled Picturing Modernity: The Photography Collection, this fascinating exhibition is a showcase of SFMoMA’s photography collection that includes pictures form the mid-1800s to the present, highlighting key moments in the development of the medium. The presentation I viewed focused on topographic photography, highlighting pictures that focus on the natural and architectural surfaces of the land, from 19th-century surveys of cultural monuments to contemporary works.

One of the fascinating sections presented in this major photography exhibit focused on six antique photographic processes. Excellent examples of each of the processes were featured. Below are SFMoMA’s brief description of each of the historically important photo printing technologies of yore that the museum featured.

AMBROTYPE

Ambrotypes are named for James Ambrose Cutting, who popularized the process during the 1860s in the United States. A glass plate is coated with collodion (gun cotton dissolved in ether) and dipped in a silver nitrate bath, making it sensitive to light. While still wet, the plate is exposed in a camera and developed to produce a negative with whitish tones in the light areas and clear glass in the dark areas. Backed with an opaque coating or viewed against a dark background, the areas of light and dark read as positive. Ambrotypes do not originate from negatives and are thus unique objects. They require protection in miniature cases because the glass plates and collodion emulsion are extremely fragile.

TINTYPE

Tintypes were extremely popular in America in the 1860s. They are produced on thin sheets of iron coated with an opaque black or brown lacquer. The lacquered metal is made sensitive to light with an application of collodion containing silver salts, then is immediately exposed in a camera and developed. The process is essentially the same for producing a collodion negative, and, in fact, tin types are negative images; it is the dark, lacquered background that produces the effect of a positive image. Tintypes were often placed in decorative frames or miniature cases like those used to protect daguerreotypes and ambrotypes. Hand painting was frequently employed to compensate for their lackluster tonal range.

ALBUMEN PRINT

Widely used until the 1890s, albumen prints are characterized by their glossy surfaces and sharp image definition. They are made by floating thin paper in an egg-white (or albumen) mixture containing salt. This mixture coats the paper, giving it a smooth, shiny surface when dry. The paper is then made light sensitive with silver nitrate and exposed to sunlight in contact with a negative, which is typically made of glass or waxed paper. The resulting image is permanently fixed by bathing the paper in a solution of hyposulfite and water. Toning during processing, often with gold chloride, yields variations in color and make the image more permanent.

CYANOTYPE

Cyanotypes were first introduced in 1842 by Sir John Herschel. They are made by brushing ordinary paper with an iron-salt solution that produces bright blue pigments when exposed to light. Once dry, the sensitized paper is placed in sunlight while in contact with a glass plate negative or other image source, such as a plant specimen, until the image appears on the paper. The paper is then washed in water to stop the development process. The materials used to make cyanotypes are essentially the same as those used today to reproduce architectural blueprints.

SALT PRINTS

William Henry Fox Talbot first introduced salt prints in 1839. They are made by immersing ordinary writing paper in salt water and then coating one side with a solution of silver nitrate, thereby embedding light-sensitive silver chloride in the paper’s fibers. A negative is placed on top of the sensitized paper and exposed to sunlight until an image appears. the print is then made permanent with sodium thiosulfate (hypo) and can be toned for greater permanence and richer hues. Occasionally the paper is pretreated with a thin coating of albumen, which makes the surface slightly glossy. Because multiple salt prints can be made from a single negative, this process made it feasible to reproduce photographs in albums and books.

WOODBURYTYPE

The woodburytype process was patented in 1864 by Walter Bentley Woodbury and used until about 1900 to create continuous-tone photographic reproductions in books. A glass sheet dusted with talc is coated first with collodion and then with bichromated gelatin. When illuminated under a negative, the gelatin hardens in proportion to exposure. The gelatin is then separated from the talc-dusted glass and washed to remove any remaining unhardened material. The result is a relief that is applied under heavy pressure to a lead plate, creating a mold. The mold is inked with pigmented gelatin–usually purplish brown in color–and the image is transferred to paper in a printing press. Unlike other early photo-mechanical processes, woodburytypes lack a grain pattern and are admired for thier luminosity and subtle tonal range.

The photographs in Picturing Modernity: The Photography Collection date back to the invention of the medium. Learn more about the photographic processes from a fully illustrated information sheet that you can freely download or view in a convenient single-page PDF format.

Nowadays, although it can still be done, hardly anyone does any of the above photo printing methods anymore. However, it’s always a good idea for digital shooters to learn their roots, particularly to discover how difficult it used to be to print pictures, and hopefully, along the way, gain appreciation for the ease and convenience afforded by today’s digital photo printing techniques.

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Written by dominiquejames

April 2, 2008 at 11:31 PM

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