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 [graphic] National Register Bulletin: How to Improve the Quality of Photographs for National Register Nominations

U.S. Department of the Interior, National Park Service

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I. A Brief History of Photography and the Photographic Process

Until the invention of cameras and photographs, followed by the development of a practical way to print photographs in newspapers, the reading public pictured an event with the aid of an artist's rendering. In the 1860s, photographers recorded some events in American history for the first time. When photographer Matthew Brady exhibited photographs of corpses on the battlefield in 1862 at his New York City gallery, the public saw the gruesome realism of broken bodies for the first time. (See below.)

As the settlers pushed westward, photographers were there. They recorded the completion of the Transcontinental Railroad. Who has not seen the famous picture of the two locomotives meeting at Promontory Point, Utah? (See page 2.) Photographer, William Henry Jackson, spent years in the West with Ferdinand V. Hayden's expeditions recording the landscape. Jackson was the first to photograph Mesa Verde in Colorado (1874) (See page iv.) and the legendary Mount of the Holy Cross (1873), near Leadville, Colorado, among other places. (See page 2.)

photograph of Confederate dead from one of Stephen D. Lee's batteries lying east of the Dunker Church, Antietam, near Sharpsburg, Maryland, September 1862.
Confederate dead from one of Stephen D.Lee's batteries lying east of the Dunker Church, Antietam, near Sharpsburg, Maryland, September, 1862. (National Park Service Historic Photograph Collection. Alexander Gardner, 1862)
The first true photographs were exposed on metal that had been sensitized to accept an image. Daguerréotypes, named for their French inventor L.J.M. Daguerre in 1837, were metal sheets upon which a positive silver image was affixed. (See page 3.)

The inventor of the first process which used a negative from which multiple prints were made was William Henry Fox Talbot, a contemporary of Daguerre.

Tintypes, patented in 1856 by Hamilton Smith, were another medium that heralded the birth of photography. A thin sheet of iron was used to provide a base for light-sensitive material, yielding a positive image.

Photography advanced considerably when sensitized materials could be coated on plate glass. The first glass negatives were wet plate. They had to be developed quickly before the emulsion dried. (In the field this meant carrying along a portable process had been invented and patented which freed the photographer from the necessity of developing each print immediately.

In 1889, George Eastman, realizing the potential of the mass market, used a newly invented film with a base that was flexible, unbreakable, and could be rolled. Emulsions coated on a cellulose nitrate film base, such as Eastman's, made the mass-produced box camera a reality. Using box cameras, amateur photographers began to document everyday life in America. Eastman's first simple camera in 1888 was a wooden, light-tight box with a simple lens and shutter that was factory-filled with film. The photographer pushed a button to produce a negative. Once the film was used up, the photographer mailed the camera with the film still in it to the Kodak factory where the film was removed from the camera, processed, and printed. The camera was then reloaded with film and returned.

photograph of  "East Meets West at Promontory Point, Utah"
East Meets West at Promontory Point, Utah. Representatives from the Central Pacific and Union Pacific Railroads shake hands over the final spike in the Transcontinental Railroad, 1869. (Yale collection of Western Americana, Beinecke Rare Book and Manuscript Library. Andrew Joseph Russell, 1869)

In the early 1940s, commercially viable color films (except Kodachrome, introduced in 1935) were brought to the market. These films used the modern technology of dye-coupled colors in which a chemical process connects the three dye layers together to create an apparent color image. This system is still used for color.

Photographic Films

Black and white film is long lasting and more permanent than color film. The first flexible films, dating to 1889, were made of cellulose nitrate, which is chemically similar to guncotton. A nitrate-based film will deteriorate over time, releasing oxidants and acidic gasses. It is also highly flammable. Special storage for this film is required. It is highly explosive and should be kept at low temperatures, in sealed bags, in fireproof vaults.

Nitrate film is historically important because it allowed for the development of roll films. The first flexible movie films measured 35-mm wide and came in long rolls on a spool. In the mid-1920s, using this technology, 35-mm roll film was developed for the camera. By the late 1920s, medium-format roll film was created. It measured six centimeters wide and had a paper backing making it easy to handle in daylight. This led to the development of the twin-lens-reflex camera in 1929. Nitrate film was produced in sheets (4 x 5-inches) ending the need for fragile glass plates.

photograph of Mount of Holy Cross, near Leadville, Colorado
Mount of the Holy Cross, near Leadville, Colorado. (National Park Service Historic Photograph Collection. William Henry Jackson, 1874)

Triacetate film came later and was more stable, flexible, and fireproof. Most films produced up to the 1970s were based on this technology. Since the 1960s, polyester polymers have been used for gelatin base films. The plastic film base is far more stable than cellulose and is not a fire hazard.

In the past decade, film has become far less grainy and is greatly reduced in contrast. New technology has produced film with T-grain emulsions. These films use light-sensitive silver halides (grains) that are T-shaped, thus rendering a much finer grain pattern. Films like this offer greater detail and higher resolution, meaning sharper images. The traditional rule that slower film produces finer grain is no longer true. The finer grained films are still slower, that is, the ISO rating is lower, but they are much less grainy and have much less contrast.

A recent development in black and white film is a process that uses color film technology to develop and print black and white films. It is easy to take a roll of this film to a one-hour processor to get back prints quickly. However, the film has a purple tint to it, as do the prints. Additionally, because of the color processing, the life of the film or prints is highly suspect. (National Register requirements forbid the use of such films for nominations because, like all color films, they do not meet the documentation standards set by the National Register.)


photograph of The General Post Office, Washington, D.C.
The General Post Office Washington, D.C., 1839, designed by architect Robert Mills. This photo is a copy of a daguerréotype of the building taken in 1846 by John Plumbe. (Library of Congress Daguerréotype Collection)

Photographic Prints

Traditionally, linen rag papers were used as the base for making photographic prints. Prints on this fiber-base paper coated with a gelatin emulsion are quite stable when properly processed. Their stability is enhanced if the print is toned with either sepia (brown tone) or selenium (light, silvery tone).

Paper will dry out and crack under poor archival conditions. Loss of the image can also be due to high humidity, but the real enemy of paper is chemical residue left by photographic fixer. (See Glossary.) In addition, contaminants in the water used for processing and washing can cause damage. If a print is not fully washed to remove all traces of fixer, the result will be discoloration and image loss. Staining also can occur on improperly processed negatives. The accepted current standard for adequate washing to remove the fixer is a minimum of 30 minutes with a total change of water every five minutes. (Commercial chemical preparations may be added to the bath to speed up the process.)

A recent innovation in papers is the resin-coated, or water-resistant, paper. The idea is to use normal linen fiber-base paper and coat it with a plastic (polyethylene) material, making the paper water-resistant. The emulsion is placed on a plastic covered base paper. The problem with resin-coated papers is that the image rides on the plastic coating, and is susceptible to loss. Because resin-coated paper is considered unstable, the Prints and Photographs Division of the Library of Congress will not accept prints made with it. The National Register will accept prints on resin-coated paper provided they contain no evidence of residual chemicals, fading, or yellowing.

Only fiber-base paper, specially processed to archival standards, is acceptable for archival purposes. Most of today's commercially made prints are on resin-coated paper. Whether the print is from the corner drug store or a professional laboratory, it is almost certain to be made on resin-coated paper. As stated above, resin-coated paper is acceptable for National Register photographs provided the prints made with it have been properly processed and washed. Machine processed prints such as those made with a stabilizer are not acceptable because the chemicals have not been completely washed out.

photograph of a typical field set-up of the Civil War era
Taken near Savannah, Georgia this photograph shows a typical field set-up of the Civil War era. The wagon carried chemicals, glass plates, and negatives. The buggy to the left could be used as a field darkroom. Before a reliable, dry-plate process was invented (ca. 1879) photographers had to develop negatives quickly before the emulsion dried. (Library of Congress, Prints and Photographs Division)

Another film medium that is not suitable for photographic permanence is color. Color film and prints are not stable because organic dyes are used to make the color image. The image will quite literally disappear from the film or paper base as the dyes deteriorate. Kodachrome, dating to the first third of the 20th century, appears most stable and examples exist that are half a century old. Color transparency films by Fuji of Japan are proving to be stable, but only age (not accelerated aging tests) will reveal the truth.

Most recently, new techniques, along with some old ones, are creating what is called permanent color prints. The old fashioned dye transfer process has been reintroduced by two small companies. New printing methods using computer-generated thermal dye prints, digital images, supposedly highly stable pigments, and other technology claim to offer permanency for color media. It remains to be seen whether these claims can be substantiated. Other printing methods such as dye sublimation (a process for making paper prints that is created on a computer as a digital image), color Xerox, color laser, ink jet color, and other computer printers are so new that there is no data on how long these media will survive. Digital permanence is still a matter of speculation. Jeff Rothen-berg in an article in Scientific American has recently raised disturbing questions about the longevity of electronic media. (See Bibliography for citation.)

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