In 1842 he began using potassium ferricyanide as a light-sensitive coating. The resulting rich deep blue color, also known as Prussian blue for the watercolor pigment of the same name, is extremely stable. The original cyanotypes that Sir John made in the 1840s are still clear and beautiful. Because the process requires ultraviolet light for exposure, the images are also sometime known as sunprints. A somewhat modified version of this process is the basis for the classic blueprint that is used by architects and builders.
The fine-art version of cyanotype is able to convey a very full range of tones, based on a negative which is the same size as the final image. This negative is usually created as a second step from the original smaller negative (35mm, 2-1/4 or 4x5). It is contact-printed using a source of ultraviolet light, like the sun or an ultraviolet exposure unit. The paper is coated with a mixture of potassium ferricyanide and ferric ammonium citrate.
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About Cyanotypes |
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Cyanotypes are one of the very first photographic processes, and also one of the most archival. The process was discovered nearly 160 years ago by the English polymath and inventor, Sir John W.F. Herschel. Herschel, in fact, invented the very term "photography".
After the contact printing the cyanotype is developed
in plain water. The resulting deep blue image seems to exist in its
own mysterious world, almost in a heightened way of seeing. Perhaps
by its simplicity and elegance, it seems to me a distillation of vision.
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| Images available for purchase. Contact me via email at edwardaites@yahoo.com for pricing information. All images Copyright 1992-2007 by Edwardo Aites. No reproduction or redistribution in any form whether digital or print without prior written consent. |
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