Photographic ImagesBy David MacLean
How to identify originals and detect fakes
Early photographic images--daguerreotypes, ambrotypes and tintypes-- were all one-of-a-kind of images. That is, the metal or glass plate exposed in the camera was also the final photograph. To get three final photos, you needed three exposures and three plates. Quick, cheap multiple images of the same subject were really not available until the introduction of film negatives and positive printing papers around 1870. This system is basically the same as we use today.
Film, usually on a roll, is loaded into the camera and exposed to the subject. The film records a negative image of the subject--light areas are dark, dark areas are captured as light. Light is shined through the developed negative onto a printing paper which makes the final photo we hold in our hands. The main advantage of this system is that many final images can be produced from a single negative.
The first photographic paper, called albumen, was invented about 1850. As its name suggests, the main ingredient coating the underlying paper was made from salted egg whites. The process wasn't practical until a suitable underlying paper was developed in the 1860s. Paper had to be thin, yet strong when wet. It also needed to be exceptionally pure--the slightest trace of foreign matter would react with other photographic chemicals and cause staining. Albumen mixtures were applied wet by the user up until about 1870 when dry factory coated albumen paper became available. Wet or dry, all albumen paper had to be sensitized in a silver nitrate solution by the photographer before use.
Original albumen paper has only two layers, 1) the paper base, 2) the albumen coating. Gelatin, collodion and all modern papers have a third layer made of barium sulfate. This layer, called baryta (pronounced ba-rie'-ta), is sandwiched between the top layer of emulsion and the paper base. In original albumen prints, you can look directly through the albumen coating and see rag fibers which form the old paper base (Fig. 2). The baryta layer in modern papers, however, prevents you from seeing the fibers and is one of tests you can use to separate old from new papers.
POP- Printing Out Papers
Albumen coated papers remained the standard print material until the 1890s when it was gradually replaced by paper with gelatin and collodion coatings. All three of these papers- - coated with albumen, gelatin or collodion - are called printing-out papers (POP). With POP, the final image is formed by placing a film negative in direct contact with the coated paper. The negative and paper are held together in a frame and exposed to sunlight. Sunlight passed through the open areas of the negative to expose the paper underneath until the image was the desired darkness. The paper was then removed from the frame and preserved with a chemical bath and water rinse (see illustration in Fig. 3).
Processing ended at this point for collodion and gelatin coated papers but albumen paper required an additional step called toning. Toning was a final chemical wash that gave albumen images their warm brown or purplish overall color. Without toning, albumen papers were an unattractive yellow. Gelatin and collodion coated papers did not require toning because they were treated at the factory and supplied ready-to-use.
Although POP did allow multiple prints to be made from a single negative, the process was slow and unpredictable. Images would form only after long exposure to sunlight and a cloudy day meant no printing. Prints were also limited to just the size of the negative with most prints no larger than 8 x 10 inches.
DOP- Developing Out Paper
The slower POP system was replaced during the 1880s by a much faster process called developing out papers (DOP). Unlike the earlier POP - in which sunlight produced an image on a dry sheet of paper - DOPs had to be dipped into or "developed" in a chemical solution to produce an image. This meant photographers could now make images as soon as the negatives were ready which included at nighttime and on sunless days.
By the turn of the century, an adequate supply of high quality linen and cotton rags, from which photographic paper was made, became increasingly difficult to find. Pigments, dyes, and other impurities used in manufacturing modern cloth made cloth rags and scraps unsuitable for photographic papermaking. Since the 1930s, virtually all photographic paper has been made from wood pulp.
Paper Prints - Old or New?
The following points will be helpful in determining if a paper print is antique or modern:
(1) Is the print mounted? Thin paper backs and moisture absorbing coatings cause severe curling in unmounted pre-1900 photographs. Unmounted albumen prints, for example, will roll up into a cylinder as small as a pencil. Most, but not all, mid-19th century mounting board was a solid color throughout. By the turn of the century, mounting board usually had a gray paper core between colored paper--usually a dull gray or tan--on tops and backs. Most modern mounting board has a color layer on the top surface, a white core and white back layer. Some modern mount board is made in solid color from front to back but all I have seen are pastels, not the somber gray and tan colors of the Victorian era. Beware of photos that are sold as old if they are on inappropriate mounting boards (Fig. 5).
(2) Is the photographic paper the right thickness? Butt a piece of ordinary 20-pound paper up against the edge of the print and run your fingernail across the joint. Most 19th century prints are about the same thickness as a single sheet of copy paper; most modern prints will be on a thicker base (Fig. 6). NOTE: "20 lb" is a common term used to describe the weight or thickness of paper. This is usually stated on the cover of pads or wrappers of typing papers or copying papers.
(3) Is the print a brown or sepia tone? If the photo is sepia toned, look for signs of fading. It is very rare to find an original sepia toned photo without some sign of fading. If a warm-tone print of a 19th century image has no fading - beware - it could be a copy. This test can be applied only to sepia or brown tones. Old prints which have a neutral or black tone are much less subject to fading and can't be dated by this this test.
(4) Is there silvering or mirroring on the surface of the photo? Look at the picture at an angle and examine the edges or the darkest areas of the image. You should see a metallic sheen on the surface of the print. This sheen, called silvering, results from long-term exposure of the silver nitrate in the print to air. This condition takes years to produce and would be rare in a recently made photo. Most old DOP prints will have some silvering.
The time it takes to develop silvering depends upon humidity, storage conditions and air quality. A Kodak Dataguide from 1947 containing sample swatches from twelve different Kodak papers shows silvering in eleven of the twelve examples. A similar publication from 1966 with eleven sample prints shows no silvering in any of the examples. Photographs made by other processes--such as platinotypes, carbon prints, and matte collodion prints--are not generally subject to silvering and would not be detected by this test.
In other words, the presence of silvering is a good indication that a print is old; the absence of silvering is not proof that a print is new. Although easy to remove, silvering is akin to the patina on old copper and should be left intact.
(5) Does the print have a full range of tonal values? A well-made, old original print will have deep dark shadows, clear highlights, and a full range of tones in between. It is very difficult to make a reproduction photograph that will have the full tonal range of the original.
You can think of tones as steps or divisions along a line. One end is light, the opposite end is dark and all the steps in between shade gradually from light to dark. A copy of an original photo may only contain a few steps. If the copyist tries to get the light areas white, the darkest blacks become muddy; printing for black leaves the whites grayish. With practice, the shortened tonal range of copies can be recognized and used to separate new from old. Be especially wary of publicity stills of entertainment or sports celebrities--most are copies and lack the full range of tones of original photos.
When collectors speak of real-photo postcards, they generally mean black and white photographs sent through the US mail as postcards between 1890 and WW I. Originals are collected for their depiction of period occupations, life-styles and historic subjects. There is a difference between real-photo postcards and picture postcards. Real-photo postcards are individual photographs treated as postcards by the US postal service. The later term, picture postcard, usually refers to postcards made on a printing press and which will show the typical dot pattern of the modern printing process.
There are substantial numbers of faked real-photo postcards in the market. The new cards feature early 20th century views and are frequently being sold at antique prices. Some new photo cards even have a copy of a vintage 1910-1930 "AZO" stamp box copied on the new cards (Fig. 9). One way to avoid buying a reproduction is to buy only those cards bearing a cancelled stamp and postmark of the era depicted in the photo.
Detection with Black Light
Preliminary tests show that black light (ultraviolet radiation) can be a useful tool in distinguishing modern prints from old. The chemical brighteners in modern papers fluoresce under both short and long wave black light. Prints known to be of recent vintage show the greatest fluorescence with the brightest glow produced from the back side; tests on the image side vary. Some fluoresce brightly throughout the image, others only through the highlights or along the outer margins. In case of doubt with a mounted print, direct the black light at the edge of the print. The edge of a new print will glow brightly even if the fluorescence does not show through the image. Further tests may be needed.