Chapter 9
Transferotypes and Miscellaneous Bases

This chapter discusses atrephographs, diazotypes, Eburneums, enamelines, ivorytypes, and transferotypes.

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The technique of moving an image from one substrate to another was widely practised, for a variety of reasons. Photographers explored every money‑making possibility of getting ahead of their competitors, but there was also a fascination with the flexible creativity of the new art. In addition to readily available commercial plates and papers for routine work, there were many "do-it-yourself" recipes for light sensitive emulsions that could directly print pictures on almost any surface.

Transferotype
This name does not refer to a process associated with any particular insidual. Transferotype paper consisted of gelatin silver bromide on top of a layer of water soluble (unhardened) gelatin. After processing the exposed image, it was pressed against another substrate while still wet. The application of hot water to the back of the picture melted the soluble gelatin so that the paper could be peeled off. The gelatin image was reversed if viewed from the back, and was nearly transparent, permitting hand tinting and special effects. Transfers were made to many bases, such as wood, metal, colored glass, ivory, leather, and fabrics. Metals were usually iron, copper, or brass; aluminum was not a commercial product until the Hall process was invented in 1886.

Transfers were also made by peeling the emulsion and placing it face up on a second substrate. Care was required to avoid wrinkles and air bubbles, but it did not reverse the image. Contact transfer, as mentioned, reverses the image, and this was sometimes one reason for doing it.

Silver bromide paper was first manufactured on a large scale by Swan (England) in 1879, but transfers were made long before that date with collodion, bichromated gelatin, and albumen emulsions. Workers attempting to make flexible negatives and stripping films tried various combinations of gelatin, collodion, albumen, and rubber (see chapter 3). There is no general recognition guide except analysis. If the top layer is collodion, the reflected appearance is milky, while gelatin is dark.

Emulsions on Other Substrates
Sensitized collodion syrup and bichromated gelatin could be poured on almost any surface that could withstand processing and that did not dissolve in the emulsion. Even then, substrates such as cardboard, leather, and fabrics could be varnished or "japanned". The latter was a generic term; real "japanning" required baking, which of course could not be done on temperature-sensitive or flammable materials.

If the surface was flat, a simple contact exposure was made, while projection enlargements could be made on curved surfaces. The reprint of the 1864 edition of Towler [145, 150‑151] has detailed recipes. The same variety of substrate materials mentioned above for transferotypes could be coated with liquid emulsions. Some of the processes that were successful enough to be dignified by name are described below:

Atrephograph
This name was applied to several processes. Cardboard and leather were coated with collodion and bichromated gelatin on top of japan varnish. Images were also applied to the same bases by transfer processes.

Diazotypes
There is a large class of organic compounds that are listed under the prefixes "azo" and "diazo" in organic chemistry references, having in common a nitrogen atom in each molecular arrangement. This class of compounds was discovered in Germany in 1860 and was very extensively studied as the basis for making dyes. Some of the compounds are light sensitive, and this property was utilized by Adolf Feer in his 1889 patent. Feertypes were not commercially important, but many workers experimented with them, and they are the basis for the important "Ozalid" process for copying large industrial line drawings. Diazo compounds can be made in many colors, usually low in color saturation, and have been applied largely to paper and fabric bases.

Eburneum
This process was invented in 1865 by J. M. Burgess. A collodion emulsion was applied to a waxed glass plate. After exposure and processing, the surface was coated with a mixture of gelatin and zinc oxide. The collodion was then peeled off the waxed glass and remounted with the back side out. The white zinc oxide pigment on the former front surface simulated an ivory backing. The process reversed the image, but the original negative could be reversed for the exposure.

Ivorytype
Miniature portraits on ivory had been painted by artists for many years, but they were expensive. In 1855 J. E. Mayall (England) patented a cheaper process. He made tinted collodion or albumen portraits on artificial ivory (the newly invented celluloid), and called them "ivorytypes".

Ivorytypes were also made by adhering paper prints to glass, usually with the image side against the glass, either by waxing or by applying them wet from processing. Wax made the paper translucent, and tinting made a lifelike effect against a white background. Welling [149, 136] illustrates a double print ivorytype with two tinted translucent paper prints, each on separate glass backings and bound in register.

The name "ivorytype" seems to have been a generic name applied to pictures that looked as though they were on ivory. Ivorytypes were sometimes called imitation Eburneums, which in turn were imitation ivory pictures. In spite of detracting descriptions, many of the pictures were quite pleasing as well as photographically faithful.

Microscopic examination can detect fibers in paper‑based ivorytypes, compared with the fiberless collodion. It may be possible to see zinc oxide grains in Eburneum pictures.

Ivorytypes are described in Cassell's [84, 313], Gernsheim [61, 344], and Welling [149, 136].

Enamelines and Fired Images
The art of firing decorated ceramics is perhaps 10,000 years old. The concept of firing photographic images on inorganic substrates seems to have originated in 1854 with the Frenchmen Bulot and Cattin whose English patent covered transferred and fired collodion pictures. Thereafter many photographic processes were applied to and fired on glass, porcelain, and enameled metal. It is difficult to generalize on appearances because of the wide variety of materials and techniques. Untinted photographs contained silver, chromium, platinum, or iron, along with carbon from organic binders. These chemical elements dissolved in the ceramic bodies, and the resulting colors depended on the element, the ceramic, and on whether the firing atmosphere was oxidizing or reducing. In addition, ceramic pigments were often applied as dyes and tints on top of the photographic image. Most ceramic pictures were miniature portraits, but Gernsheim mentions Joubert's efforts in England to make stained glass windows as large as 17 1/2 by 24 inches.

Microscopic examination can distinguish between fired images and coated emulsion prints. Enamelled metal was usually copper. Burbank [28, 165‑189] gives detailed recipes for several processes. Other descriptions are found in Eder [48, 566‑568], Gernsheim [61, 342‑344], and Towler [145, 308‑309]