Anna Atkins, Papaver rhoeas, 1845

Cyanotype is one of three photographic contact printing methods that rely on the photo-reduction of ferric ions. (The argentotype or van Dyke and the platinum/palladium processes are the other two.*) Richard Benson’s The Printed Picture tells us that cyanotype is how the blueprint is referred to in fancy circles. The process exploits the ability of ferric iron compounds to become ferrous when exposed to high levels of light. Prussian blue was the material originally used. Prints can be made on paper or fabrics (though not synthetic fabrics). You coat the material to be printed (the coating looks pale yellowy green), and hang it up to dry in the dark. Lay on top of it the object to be reproduced and expose the lot to bright light for up to 15 minutes, and there you are. We book-making folks are familiar with the process (or at least the tangible results of the process) in the blues which we often check just before a book is printed. Architectural and engineering drawings used to be reproduced by the same process, and thus our word blueprint has come to mean a planning outline.

If you fancy trying your hand at cyanotype Jerry’s Artarama will sell you jars of Jacquard’s potassium ferricyanide and ferric ammonium citrate which when combined will set up the process. All you need to do is treat your substrate (if you didn’t buy pretreated sheets from them) and place on top of it any object which will cast a shadow, leave it in the sun for 3 to 15 minutes, and there’s your image. Among the shadow-casting objects can of course be a negative, whether of a photograph or a page of type. A film positive will work too. A negative will show the type or image blue and the background white, while a positive original will give the opposite result. (Book blues tend to be printed on a yellowish paper.) Most excitingly Artarama offers you self-portrait possibilities: “With Jacquard’s Cyanotype Pretreated Mural Fabric you can actually create a full-body print by laying [sic] on top of the mural fabric for the duration of exposure while not moving. The creative possibilities for Photographers, Mixed Media Artists, and Quilters are endless!”

It all does seem pretty straightforward, as this short video demonstrates:

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The invention of photography in 1839 provoked a lot of experimentation with the interaction of different chemicals with light, and Sir John Herschel came up with the formula for cyanotype in 1842. John George Children, who had been present at the Royal Society meeting when Henry Fox Talbot had first presented photography to the world, kept his daughter Anna Atkins (1799-1871) fully informed of developments. She had been drawing plants and seashells, and frustrated by the lack of illustrations in an 1841 book about algae, set to in 1843 to use Herschel’s process to create the necessary illustrations. The Guardian recounts her story, and tells us there’s an exhibition called New Realities at the Rijksmuseum running until 17 September, featuring Atkins’ work. Unfortunately their link takes you to the wrong show. This link will reveal the Rijksmuseum’s immense collection of Atkins’ work.

I had quietly assumed that cyanotype would be so named because of its blue color (cyan, derived from the Greek κύανος, dark blue, being the name for the blue ink in the CMYK process). But no: according to the Oxford English Dictionary it gets its name from the involvement of cyanide in the process. As their one supporting reference they quote Sir John Herschel from his original publication of the discovery in The Philosophical Transactions of the Royal Society: “If a nomenclature of this kind be admitted . . . the whole class of processes in which cyanogen in its combinations with iron performs a leading part, and in which the resulting pictures are blue, may be designated by this epithet. The varieties of cyanotype processes seem to be innumerable.”


* These three printing methods are differentiated by color. Cyanotypes are blue, argentotypes are sepia brown (which is why they were named after van Dyke apparently), and palladium prints are browny grey. The color derives from the different effects of different light-sensitive chemicals used.