Cyanotype Information
Essay by Frances Cullen
Sir John Herschel invented the cyanotype process in 1842, only three years after the invention of photography.  He presented the chemistry of the process in his paper “On the Action of Rays of the Solar Spectrum on Vegetable Colors and on Some New Photographic Processes” to the Royal Society in that year. The initial part of the paper introduced the Anthotype process, which was a photographic process that produced an image using crushed flower petals, alcohol, and extended exposure times.  Subsequent to this, Herschel presented his research on a photographic process based on the light sensitivity of iron salts which produced a blue-toned image: the cyanotype.  Herschel himself assigned the process this name, which is a derivation of a pair of Greek words thought to mean “blue” and “imprint.”  Herschel is credited as the inventor of a number of photographic processes, including the Chrysotype, a gold print, and the Kallitype, which is in fact a photomechanical process.  The cyanotype is, nevertheless, considered the first successful non-silver process, although it did not gain popular usage for several decades after its invention.  Cyanotypes are also referred to as blue prints and as Ferro-prussiate prints, and are almost always identifiable by their dark blue color.  (Cyanotypes can now be toned to produce a variety of colors.)  When viewed under magnification (figure 1),
figure 1: microscopic image of untitled cyanotype by Steve Morrison; see figure 3
the single-layer structure of the cyanotype becomes evident.  The paper fibers should be visible and the dye solid and evenly distributed.
The cyanotype process is noted for its simplicity and convenience.  It has frequently been observed to be the ideal process for a beginning student of alternative photographic processes because the chemicals are inexpensive and non-toxic, and the process is uncomplicated and does not require a dark room.  Further, cyanotypes can be successfully created on nearly any kind of organic support, including most papers that will not disintegrate in water, cotton and linen based fabrics, and wood.  On the simplest level, the process is based on the light sensitivity of iron salts. The chemicals required are Ferric Ammonium Citrate (in the green powdered form) and Potassium Ferricyanide.  The process involves the completion of two basic chemical reactions after these chemicals have been combined in solution and brushed onto the support.  First, when the Ferric Ammonium Citrate is exposed to ultra-violet light, the ferric iron is photochemically reduced to ferrous iron.  The ferrous iron subsequently reacts with the Ferricyanide to produce Prussian Blue, the substance that gives the cyanotype its final blue hue.  Prussian Blue is an indigo-colored dye that was discovered in 1704.  It was soon widely used as an artist’s pigment.  Essentially, Prussian Blue is the commercial term for the chemical compound Ferrocyanide. The ferric iron ions in the Ferricyanide have been replaced by the ferrous iron ions to produce this compound. The chemical structure of the Prussian Blue molecules varies.  This fact will be discussed further as cause of some of the problems with the process that Mike Ware’s “New Cyanotype Process” seeks to correct.  
As previously stated, the cyanotype was not widely used until approximately the 1870s.  It was, however, taken up nearly immediately by Anna Atkins, the first female photographer.  Atkins was a botanist who used the cyanotype process in the first photographically illustrated book, “Photographs of British Algae: Cyanotype Impressions,” in 1843.  Atkins published her series of leaf prints, or photograms, even before William Henry Fox Talbot’s “The Pencil of Nature.”  (According to Terry King’s description on Hands-on Pictures, a photogram is a cyanotype produced by exposing the sensitized paper to light with a (flat) object held against it, creating a white “shadow.”) (Figure 2)  
Figure 2: Anna Atkins. Asplenium Pramorsum (Jamaica)
Herschel himself intended for the cyanotype to be used as a method of reproduction.  He used it to make copies of notes and mathematical tables.  It would later achieve a significant level of popularity and utility as an inexpensive, simple, and practical way for engineers and architects to duplicate engineering plans and architectural drawings, dubbed “blueprints”.  This use of the process was initiated in 1876 at the Philadelphia Centennial Exposition and maintained popular usage for about 50 years.  Its popularity was encouraged and enabled by the large scale industrial manufacture of blueprinting paper beginning in the 1880s.  
The brief popularity of commercially produced cyanotype paper also encouraged other uses of the cyanotype during this period.  From nearly the time of its invention to the turn of the century, a small but notable group of photographers found the cyanotype useful for the production of proof prints.  The cyanotype is appropriate for this purpose because of the permanence and stability of the image as well as the convenience, relative safety, and low costs of the process.  According to Richard T. Rosenthal on the Vernacular Photography website, “Henri le Secq, Thomas Anschutz, Edward S. Curtis, Thomas Eakins, Charles F. Lummis, and A.L. Coburn [are] all known to have made cyanotypes.”  Lummis, for example, was a photojournalist who found the cyanotype useful for printing his expeditionary photographs of the American Southwest.  Because the process does not require a darkroom, printing was made possible under the difficult conditions of on-site photography.  As early as the 1850s, M.J. Diness used the cyanotype to print his collodion wet plate negatives taken around Jerusalem.  Edward S. Curtis and Arthur Wesley Dow made cyanotype proof prints in the early 20th century.  Peter Marshall wrote in his article for the About Photography website, “Further interest in the blueprint – other than as a proofing material – was largely because of its resistance to fading.  Most early silver prints were found to be at least partly faded after a few years, and various investigations were made both to reduce the fading of silver prints (particularly with longer wash times) and to look for alternative processes.”  Apparently, for this reason, Henri le Secq was so concerned about the loss of his work through fading that at some point in the 19th century he made cyanotype prints from most of his best original negatives.  The cyanotype was also used to a small degree for the purpose of documentation.  It was known to be used, for example, to record the Spanish American War, the building of the Boston elevated railway line, and in the 1890s by Henry Bosse for his “view of the Mississippi.”
Around the turn of the century, the cyanotype became popular among amateur photographers – again, because of convenience and low costs.  Many examples can be found in photographic albums from the period.  Its usage also expanded slightly amongst the pictorialists, partly as a result of the marketing of the ferro-prussiate paper.  A small number of the secessionist photographers made cyanotype prints.  In spite of these small trends, however, this period was dominated by the perception of the cyanotype as a process best suited for purposes of reproduction and proofing, and was clearly not often considered a viable choice for what would have been considered “serious work.”  
This likely had much to do with the process’ many limitations.  Multiple scholars of the cyanotype have reiterated Peter Henry Emerson’s quote, “…only a vandal would print a landscape in red or cyanotype.”  While this comment represents an extreme opinion, there is truth in the observation that the blue tint of the cyanotype is not appropriate for the depiction of all subjects, although it does possess many creative and expressive possibilities and attractions.  The basic qualities that made the cyanotype useful in the period discussed above obscured photographers from perceiving its aesthetic and creative appeal.  The cyanotype is technically simple and convenient, and also stable and relatively permanent.  Perhaps the problem is the common misconception that the cyanotype lacks tonal range and depth.  Many cyanotypes either lack mid-tones, or have blue mid-tones and limited density in shadows.  Until roughly the 1960s, when a growing interest in printing-media and non-silver printing emerged with the publication of books about alternative photographic processes and the fine arts prints of Robert Fichter, art photographers failed to acknowledge the versatility of the cyanotype.  For one thing, as previously mentioned, it can be printed on nearly any organic support: wood, fabric, paper.  When the negative and the print are properly exposed and developed, the cyanotype can exhibit a tonal range nearly as varied as the silver gelatin print.  The cyanotype can be toned to display a variety of colors, as described in Christopher James’ cyanotype chapter in A Book of Alternative Photographic Processes. James’ chapter also notes that, “Cyanotypes can also be employed successfully as first impressions in the gum bi-chromate of blue-van-dyke processes and can also be used to delicately intensify shadow details in platinum or palladium printing.”
Currently, and since the 1960s, there has been a trend toward contemporary conceptions of the cyanotype as a versatile, expressive, and artistic medium used to create a particular effect.  For example, there are a number of publications that explore the possibilities of the cyanotype to form on such a variety of supports, and especially textiles.  Christopher James has an entire chapter devoted to “Cyanotype Variations: Fabrics and the New Cyanotype,” and Barbara Hewitt published Blueprints on Fabric: Innovative Uses for Cyanotype.  Additionally, although most cyanotypists adhere to the original formula invented by Herschel, recent years have seen variations on the process, most significantly with the multiple publications describing Mike Ware’s “New Cyanotype Process.”
Figure 3: Untitled, Steve Morrison from the Mira Godard Study Center
As Mike Ware has observed, and as this essay has attempted to express, there has been a growing amount of interest in the cyanotype. This is made evident by the increasing number of prints exhibited in museums and produced by contemporary photographers.  The image above (figure 3) was created by Steve Morrison, a photography student at Ryerson University in Toronto, Ontario, during the mid-1970s, as part of a student project.  This print was donated to the Mira Godard Study Center in 1976.  The image serves as evidence of the growing interest at the time in the aesthetic, artistic potential of the cyanotype.  By 1976, the cyanotype was considered a creative option within the academic photographic context, and artists were willing to explore its expressive possibilities.  This particular print shows the use of a 19th century process to depict a modern subject matter and aesthetic.  It also shows the ability of the cyanotype process to produce a relatively high contrast image.  Alternatively, the photograph also exemplifies some of the problems that Mike Ware has identified with the traditional Cyanotype process: namely, the lack of mid-tones and possibly, through the photographer’s notations (“good blue”; “30 sec. exposure”), the difficulty of achieving one’s desired outcome.
In his essay for About Photography, Peter Marshall refers to his former working relationship with Terry King from “Hands-On Pictures.”  King has expanded on their work completed in the late 1980s, recently developing additions to the cyanotype process that he calls a “Cyanotype Rex.”  The benefits of this process, which was developed even more recently than Mike Ware’s “New Cyanotype Process,” are the “liberation of the cyanotype from the standard blue” and a decreased exposure time. Essentially the difference is only the addition of a toning step.  Ware’s changes to the process, on the other hand, are more drastic, more widely discussed, and more controversial.
In his online essay “The New Cyanotype Process,” Mike Ware delineates what he considers to be the five “Disadvantages of the Traditional Process.”  To paraphrase, they are the lengthy exposure time; the inconvenience of having to store the two chemicals separately, and the tendency of the ferric ammonium citrate to become moldy; the tendency of the sensitizer to resist absorption by the paper; the difficulty of achieving the correct exposure on the print due to the solubility of the Prussian Blue; and the difficulty of achieving a pleasing range of tones.  His solution for the first three problems is to replace the ferric ammonium citrate with ferric ammonium oxalate because: “It is more light sensitive; It is not attacked by mold; and its solution penetrates the paper fibers more readily.”  Ware also adds a 25% solution of ammonium dichromate in order to eliminate potassium ions from the sensitizer, thus solving the rest of the suggested problems.
Ware’s revisions to the cyanotype process were largely well received, and his extensive research, experimentation, and writing about a variety of alternative photographic processes is generally well respected. Christopher James even claims that he is “under the illusion that [Ware] is the second-coming of Herschel.”  Ware’s process does allow for decreased exposure times and increased control of the final product; some of the problems are the increased difficulty of preparing the solutions and the toxicity of the chemicals.  Many practicing cyanotypists express doubt about whether an alteration of the traditional process was necessary at all.  With practice and skill, it is possible to achieve similarly satisfactory results using the original process.
Conservation issues are the same for both cyanotype processes.  Once again, the cyanotype is stable and relatively permanent.  In fact, although the cyanotype does have a tendency to fade when exposed to light over long periods of time, its color will be restored almost entirely when returned to darkness under non-alkaline atmospheric conditions.  Even so, it is recommended that the long-term display of a cyanotype be avoided.  The cyanotype is sensitive to alkalis, such as sodium carbon or perspiration.  Therefore it is suggested that cyanotypes never be stored in an alkaline box or used with alkaline mat board or interleaving tissue.  It is recommended that only unbuffered rag board be used.  These are the conservation issues almost universally identified; but in Cyanotype: The History, Science and Art of Photographic Printing in Prussian Blue, Mike Ware’s definitive study of the cyanotype, one further potential deterioration is suggested.  Because of the solubility of the Prussian Blue dye used in traditional cyanotypes, water damage can cause permanent loss of pigment.  Such degradation of the cyanotype image, however, is rare, and the cyanotype’s stability and permanence are qualities basic to its appeal both when used as a method of reproduction and in the production of art.
Hewitt, Barbara.  Blueprints on Fabric: Innovative Uses for Cyanotype.  Interweave Press
Loveland: Colorado,  1995.
James, Christopher.  The Book of Alternative Photographic Processes.  Delmar Thomson
Learning: Australia, 2002.
King,Terry. “The Cyanotype (or Blue Print),” Hands On Pictures.  
Marshall, Peter.  “True Blue (Cyanotype),” About Photography.  
Rosenthal, Richard T.  “The Cyanotype,” Vernacular Photography.  
Van Keuren, Sarah.  A Non-Silver Manual: Cyanotype, Brownprint, Palladium & Gum
Bichromate  SVK: Lansdowne, PA, 1997.
Young III, W. Russel.  “Traditional Cyanotype,” in Coming Into Focus: A Step-by-Step Guide to
Alternative Photographic Printing Processes, edited by John Barnier.  Chronicle Books: San Francisco, 2000.
Ware, Mike.  Cyanotype: The History, Science and art of Photographic Printing in Prussian
Blue. (Science Museum and National Museum of Photography, Film and Television:
Ware, Mike.  “The New Cyanotype Process,” Mike Ware’s Alternative Photography.
*Footnotes and citations do not appear in website format