Photozincography: Advances in Cartography

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The photographic process known as photozincography was a landmark event in the fields of photography and cartography. Developed in the nineteenth century by Sir Henry James, photozincography, or heliozincography, was a revolutionary way of copying photographic negatives onto zinc to be used for map making, outlines, engravings, and the reproduction of images. Photozincograhy is, in a sense, the first copy machine produced.

Sir Henry James was the Director General of the British Ordnance Survey which was tasked with the creation of maps in the 1850s under the British Topographical Department. Up to this point cartography was an art and photographs had become another tool used to create maps and other replications.

Photozincography is based on the insolubility of bichromate of potash- when this substance is exposed to light it allows the copying of images onto other surfaces. Photographic negatives can be transferred onto zinc for engraving, map making and more in addition to other surfaces. A bichromate mixture is brushed onto a thin piece of tracing paper and placed on the photographic negative, where the soluble parts of the mixture develop to create the positive image. This can then be copied onto other surfaces like zinc, in the case of photozincography.

This method was steps ahead of the previous ways of copying photographs; stone tablets were used prior to Sir Henry James’ invention. Zinc plates were lighter than their stone counterparts, could be transported easier, and made the mass copying of photographs simpler than in previous times. Zinc tablets could also be transported without fear of shattering, as was the problem with stone.

The field of cartography was enhanced by the invention of photozincography as it allowed cartographers to reduce large-scale maps to smaller, easier to use formats. Larger maps could be scaled down to be placed in books, used for travel or simply as geographic tools.

Creating maps from photographs could lead to distortion, a problem which Sir Henry James was quick to try and fix. He created the photography department for the Ordnance Survey and built a unique building in which to develop photographs more clearly and effectively. Sir Henry James’ method saved the Ordnance Survey thousands of pounds and ultimately furthered the cause of photography and cartography through its invention.

Maps created through photozincography were unable to be colorized except by hand. This was still a very time consuming process, although better than any other at the time. By the early 1900s the process had become obsolete, but served as a stepping stone for photographers and cartographers around the world.

Photozincography helped make the process of making maps cheaper as well as increasingly accessible to a great number of people. Existing maps could be shrunk down to various sizes as well as created by using photographs as a guide. Reproductions of maps, photographs, and literary works could be produced relatively easily using photozincography, ushering in a new age of knowledge for many people who previously could not access such items.

References

Hannavy, John. Encyclopedia of Nineteenth Century Photography. Photography and Reproduction Page 1098. New York 2008.

Wikipedia. Photozincography. http://en.wikipedia.org/wiki/Photozincography


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