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Tricolor and Process Printing
By the later half of the 19th century the possibilities of producing color photographs had long been discussed but no practical results were seen. The many attempts to invent color film in the early decades of the 20th century had met with only marginal success. These years saw the invention of Autochromes, Dufaycolor, Finlay Color, Colorol, and many lesser known processes that were only on the market for a few years, and while they all rendered acceptable colors in relation to the original subject, none could be said to accurately capture natural color. When measured against black & white film these color processes were a marvel, but the massive internal structure needed to hold their dyes in place created a very noticeable grain and required excessive light to use. In general all these films had to balance color saturation against brightness, which resulted in images that were somewhat grey. Many of these early photographs looked closer to being hand colored than to what we would recognize as color photography today. The various theories they were based on were sound, but the mechanics of a workable model would prove evasive until the 1930’s. when Kodachrome and Agfa Neu were introduced.
While early color photographs left much to be desired, they were still used for about thirty years as the starting point for much printed material. Even if the color was poor, they offered a more realistic foundation for determining the dispersal of color than the eye of the retoucher ever could. Postcards based on these processes do not generally make any reference to them so matching cards to a particular film cannot be made with any certainty. The color scheme on a postcard may hint at a particular film type, but even if printed with fidelity there is no guaranty of a match. Trade names are also no assurance that they were made from the film they reference since the name could only allude to a similar look. Despite the great array of films available, most photographers worked with the less expensive black & white variety and it was these photographs that most color postcards continued to be printed from with the aid of retouchers.
Autochromes are made by coating a glass plate with a layer of dyed potato starch granules that approximated the primary additive colors of red, green, and blue. After shellac is applied and dried, the plate is coated with a panchromatic silver gelatin-bromide emulsion. When the plate is exposed, the dyed grains of starch acts as tiny RGB filters before light reaches the silver emulsion. When the plate is developed a negative image is created. Afterwards the silver is bleached out and the plate re-exposed and redeveloped using an acid dichromate process. The result is a one of a kind positive transparency in full color. These transparencies were often viewed though Magic Lanterns or specially designed hand viewers called Diascopes, which were boxes that held the glass plate while the image was projected onto a mirror.
Autochrome Screen: While Autochrome plates already had an irregular pattern, their dyed particles of starch tended to clump resulting in an uneven mixture of color. This in turn created a coarse looking grain on the final transparency. The spaces between each particle were filled in with an opaque black, which slowed down exposure time.
Autochromes could not capture all nuances of color but they did produce subtle tonalities. Their colors also lack luminosity for the supporting matrix wasnít a continuous transparency but more like a screen with the space between each starchy grain dyed an opaque black. When an individual color needed to be highlighted the other colors within that particular area would be darkened reducing the brightness of the transparency even further. Its strange grainy effects aggravated by the clumping of the starch tended to yield an image that appeared to be halfway between a painting and modern photograph. The exposure time for Autochrome plates was very slow, about 2 seconds in sunlight, up to 30 seconds in a studio, and they cost more than ten times their black & white counterparts. While these features put limits on their use, millions of images were still made from them. There is little to no documentation on the photographs most postcards were made from but the appearances of many reflect the same qualities found in Autochromes.
Tricolor Print: This German postcard from 1908 is rare in that it attributes its natural appearance to its Autochrome origins. While it does have a more natural appearance than most cards of its time, the color fields remain relatively flat due to retouching and the manner in which it was printed. The green dyes in the film have been replaced with yellow ink on the card. In the detail below we can see that the RYB halftone dots have all been printed in a 45-degree rotation, with the blue forming long lines. A black halftone has been added at a 90-degree angle, but it serves as a color and not as a key plate, which keeps all the hues brighter.
The Autochrome emulsion was moved from glass plates to film in 1932 when the Lumière brothers created Lumicolor. It was soon replaced by the even faster Filmcolor in 1938 that used brewers yeast in place of potato starch. The last version, Alticolor was introduced in the early 1950’s but it couldn’t compete with more advanced multi-layered film and was discontinued by 1955.
Tricolor Print: The photographer Hans Hildenbrand began using Autochrome in 1909, and by 1911 he was using these transparencies to print tricolor postcards. He used a red, yellow, and dark blue pallet to create cards that closely resembled the original autochromes. Hildenbrand was the only official German war photographer that had his images published as postcards in natural color during World War One.
Tricolor Plus: The Swiss postcard above from 1913 is based on a photograph by Richard Worsching. While it uses a typical tricolor palette of red, yellow, and blue, it also includes an untypical extra light blue. This extended palette may be similar to that used on linen cards, but the results are something closer to a modern photochrome. Even without proper process colors to work with, some printers could still extract a great deal from an Autochrome.
Many similar screens for glass plates were manufactured about the same time such as Aurora, Veracolor, Paget, and Leto but they all met with little commercial success. In the years immediately following the First World War they generally became prohibitively expensive to use. The Thames Plates were discontinued in 1910 but a new pattern to be used in conjunction with much more sensitive plates came out in 1929 as the Finlay Color Process. Each color took the form of a rigid square almost twice the size of his previous circles. This process was used throughout the 1930ís with a brief revival in 1953 as Johnson’s Colour Screen.
Finlay Screens: Above is a pattern from a Thames Screen Plate. Each circle was 1/400 of an inch wide. Below is the pattern found on a screen from the Finlay Color Process with squares of about 240 per square inch.
Dufaycolor Screen: Here we can see the very rigid pattern used on Dufaycolor film. While popular when first introduced, the use of all such screened processes disappeared from the market by the 1950’s.
With Dufaycolor a collodion film is dyed blue then overprinted with a thin layer of green squares and red lines in translucent ink on a rotary press. After a series of bleaching and dying steps the screen was varnished and coated with a panchromatic emulsion. The emulsion could only be exposed to the single hue that corresponded to the pattern of the color grid (reseau) laid across its surface. The exposed negative could then be color separated by projecting it back through color filters. Printing plates made by this process were usually printed in gravure. Dufaycolor began being manufactured in 1931 as 35mm motion picture film and it became available for still photography in 1935. Dufaycolor was easy to develop and its speed was only about a third of black & white film, which helped to keep it popular into the 1950’s. Agfa Ultra, introduced in 1932 was a similar type of film.
Dufaycolor Film Ad: “If you want to take pictures as you actually see them - in natural color - load your camera with Dufaycolor film and shoot.” It was further promoted as capturing the most subtle tones, and for its ease of use without the need for special cameras or filters. The difficulty of traditional color photography was clearly on the public’s mind, and ads had to overcome this fear.
Agfa Color Plate
Dufaycolor Screen: While Agfa Color Plates provided a random grain without the need for opaque fillers, its color particles still tended to clump together resulting in a coarse look on the final transparency.
The Ozobrome or Carbro Process received its first commercial application in 1913 when pre-dyed tissue was sold under the Raydex name. While this was an elaborate process, it was used by professional and amateur alike because there was just no other means available at this time to create color photographs on paper. Carbon tissue could be infused with any pigment that was desired. Unfortunately many unstable pigments were employed and these prints have badly faded. Similar tricolor Carbro possesses such as Raylo and Dybro were developed in the 1920’s. Between 1931 and 1939 the Carbro Process was used to create higher quality prints under the Vivex name. Eventually this process would evolve into Cibachrome printing.
Tinted Halftone: This is not a process print but a black halftone printed over hand placed color lithographic dots. It was printed by Valentine & Sons under the Carbo Colour trade name but it has only a marginal resemblance to a carbro photo. Postcards were often associated with trade names that might increase sales even when there was no real association to the technique implied.
The Carbro method of producing color photographs was also adapted to the photolithographic process. Instead of layering all three tissue layers together to create a photograph, each tissue could be transferred to a separate litho-stone, which in turn would produce a single printed color image. The color range produced however was limited making many of these images look forced. There were also usually problems with proper color registration. This method was used between the two World Wars and was quickly replaced as soon as a more accurate color printing process was made available.
Tinted Gravure: This process printed postcard produced by Fischgrund under the Arco-Iris trade name has the washed out grainy look of an early color photograph, but it is difficult to distinguish the attributes of the transparency from those placed in by a retoucher.
The vast number of printers involved in the early postcard trade make it difficult to know the exact photographic process they based their color images on even when they are printed with process colors. While the exactness that photography provides is usually discernible from the artist’s hand, there was a plethora of experimental photo techniques that a printer might chose to make plates from. Large printing firms might find it in their interest to stick with readily available brand names, but there was also an abundance of small postcard publishers before the First World War that might choose any sort of photo to work from. While the retoucher continued to play an important role in the placement of colors, it should be noted that once even primitive color photography entered the scene, many postcards began to sport a more realistic look./font>
Process Print: While this image inspires close associations with early color film, it is difficult to tell how much of its coloration was based on a photograph or the hand of the retoucher. In the detail below we can see that the yellow plate is off register preventing a true rosette pattern to form, but this hue prints so lightly that no moiré pattern is formed.
A couple years after Kodak discovered less mobile dyes to work with, both Mannes and Godowsky were formally asked to join their laboratory staff in order to exploit this new development. In 1935 they invented Kodachrome by using old principals in a new way. Three layers of emulsion each sensitive to one of the three additive primaries, red, green, and blue would continue to be used, but the problem of light scattering was solved when they found a way to coat them all onto a single substrate. Each layer would only produce a black & white silver based image but the magic of adding color took place in the development process. Since exposure was made directly onto the molecules of the emulsion rather than through a mosaic of artificial filters, more subtitles and detail could be captured with the same three colors. The dyes on this integral tripack however were not very stable and the processing was so complicated that the film could only be develop in Kodak labs. Despite these problems Kodachrome was introduced in 1935, first as motion picture film and then released as slide film the following September.
Kodacolor: Kodak introduced color print film in 1942 but its slowness and high cost kept it out of the hands of many amateur photographers. This also prevented it from being used to create real color photo postcards as an identical look could be had with the much cheaper process printed photochrome card.
By 1938 a professional grade of Kodachrome was released after some major improvements had been made in its dyes and the processing method. This new film is first developed into a black & white negative and then each colored layer is re-exposed to filtered light and developed again one layer at a time. The separate chemical baths cause the cyan, magenta, and yellow dyes within it to couple with the appropriate silver emulsion. After the remaining silver and filtering layers are bleached out, a full natural color transparency is revealed. The first postcards to use this film for their color separations were published within a year, though the demands of a looming then actual war would curtail its commercial progress. Even this improved film took highly trained technicians to process, and their limited numbers were now engaged by the military to create enhanced recognizance photos. Use returned in the postwar years, but until the 1970’s Kodachrome remained expensive and its speed slow when compared to black & white film. Its ISO was only 6 when first introduced. These drawbacks limited its marketability with the general public, but it continued to be used by professionals and demand grew for Kodachrome based postcards that were much more convenient to buy.
Photochrome: Although this postcard was based a a Kodachrome photo by Mike Roberts, an early pioneer of chrome cards, it is not printed with process colors but a tricolor palette of red, yellow, and blue. While the introduction of Kodachrome ushered in new possibilities, the transition from older techniques was a slow process. There are many such cards as this that cannot be clearly defined.
Kodacolor: Even though Kodachrome film it associated with the birth of modern photochrome postcards, this is a misnomer. Kodachrome was instrumental to the production of these cards in the United States, but other films were used, most notably Agfacolor Neu on early German chromes. The natural color on this German card was rendered through a tricolor palette of red, yellow, and blue.
Tricolor and Process Print: After World War Two the production of photochromes (chromes) were based on both Kodak and Agfa films in Western Europe, but the Eastern Block countries and the Soviets relied almost exclusively on the Agfa process. This gives their photo based cards a slightly different look than most American cards of the same period. Although the Russian card above from 1960 was probably based on Agfacolor, its tonalities and color leave something to be desired because it was still printed in red, yellow, and blue line block as in decades earlier. There is much improvement on the Russian card below from 1967 printed in offset lithography. While process colors are used, the greens and violets are enhanced because of the film used.
Since the later 1940’s there have been a whole range of new films that have entered the market for the short and long term, each with their own particular color balance. While both color and speed have steadily improved they are all based on either the Kodachrome or Agfa Neu layering models. These films form the foundation of most imagery printed on postcards through offset lithography. With advancements in digital photography the use of film has drastically declined, and fewer postcards now use it as their starting point. The production of Kodachrome ended in 2009, and since then various forms of Ektachrome have also begun to be discontinued. While film still exists, its use in commercial printing has almost completely disappeared.