Cyanotype – Historical & Alternative Photography
This series of books, with the subtitle Historical and Alternative Photography, is dedicated to photography enthusiasts who want to learn or upgrade their knowledge about old – but nowadays increasingly popular – photographic processes.
This series is, in fact, the compilation of my notes on the photographic techniques that I’ve discovered over the years, mostly through old photographic manuals and, in recent years, through the Internet. Of course, all of these procedures have been tested in practice, adapted to our modern times, and intentionally presented with a large number of photographs to clearly present the reader with the workflow and the final result.
In each book of this collection, there are step-by-step descriptions of one or more related photographic processes. They are, of course, enriched with descriptions of “secret” techniques that have often been suppressed elsewhere. Techniques described in the collection include cyanotype, salted paper, kallitype with brown print, platinum and palladium print, gum printing, and, of course, the production of digital negatives.
To work with a particular process, it is sufficient for the reader to read a single book; more demanding readers will probably need an additional resource on digital negatives, which is a kind of basis for old photographic processes in the digital age.
The subtitle Historical and Alternative Photography is, for many readers, probably incomprehensible, since many people use the concept of alternative photography for all photographic processes from the 19th to the early 20th century. In this collection, the term historical photographic processes is used for all photographic processes discovered prior to the early 20th century (cyanotype, salted paper, platinum and palladium prints, oil and gum prints, etc…), and the term alternative photography is reserved for unconventional, creative processes, such as emulsion or Polaroid transfer, liquid emulsions photography, and the like.
Very short introduction to Cyanotype
Cyanotype, or “blue print,” was discovered in 1842 by English scientist John Frederick William Herschel (1792-1871). Due to the characteristic blue color of the resulting pictures, the procedure was relatively unpopular among the first photographers, but it was very useful for other purposes, such as copying a variety of technical and construction drawings.
The first and almost the only well-known user of cyanotype was Anna Atkins (1799 – 1871), who already in 1843 made the first photographic book with cyanotype photographs of plants. The book was called British Algae: Cyanotype Impressions, and after its publication, cyanotype drowned into oblivion.
Nowadays, with the increasing interest in all old, hand-printing photographic techniques, cyanotype is experiencing a new popularity. The technique is extremely simple and remarkably flexible, as cyanotype images can be developed on a wide range of materials, including paper, fabric, stone, and metal, and even on glass.
To produce photos with cyanotype, two chemicals are needed: Ammonium iron(III) citrate (C6H8O7 xFe3+ yNH3 – CAS #1185-57-5), also called ammonium iron citrate, and Potassium hexacyanoferrate(III) (K3Fe(CN)6 – CAS Number: 13746-66-2) with its more common name of potassium ferricyanide. Also required are paper (or any other image carrier), a negative (or a few objects, if we want to create a photogram), a printing frame (or a sheet of glass), a beautiful, sunny day or a UV lamp, and a few liters of water for development of the photographs.
The cyanotype process consists of a few simple steps. The cyanotype solution is applied to paper, which is then dried thoroughly. On this light-sensitive carrier, objects or negative film are placed. Under UV light, objects or negative film block part of the light, while on the exposed, uncovered part, the chemical composition of the light-sensitive emulsion changes. When a photograph is developed in ordinary water, the unexposed iron compounds are washed away from the photographs, while the newly-formed, water-insoluble iron ferricyanide, with it characteristic blue color, remains on the image carrier material.
Of course, cyanotype can also be quite complicated, although this is not so obvious. We can enhance the tonal range of a cyanotype image, as a finished blue photo can be bleached, toned to other colors etc…, but more about that later.
This photograph is a typical example of a photogram. On dry paper, previously coated with a light-sensitive emulsion, flowers were placed. The paper, along with the flowers, was then exposed to the sun. After development in water, the unlit parts of the image were washed and the result is seen as the contours of the white flowers.
Mixing a homemade cyanotype solution
Chemicals for cyanotype can be ordered from stores specializing in alternative photographic processes, but it is often cheaper to make your own, homemade solution. The process for doing this is quite simple, and by following the safety instructions, it is also harmless in terms of your health.
As we have already mentioned, the basic chemicals which are needed for cyanotype are ammonium iron citrate (the green kind, which contains 14.5 to 16% iron is better and is more sensitive to light), and potassium ferricyanide.
In cyanotype, there are two chemical components, which are referred to, simply, as “A” and “B”, and are made by dissolving each of the two chemicals mentioned above in distilled water. They are each then stored in two small brown-colored bottles, each labeled with the name of the chemical, the percentage of the solution, the date of manufacture, and the letter A or B. The chemicals are prepared separately as two components, since they can only be used for a few days, starting from the moment they are mixed together. The solution of ammonium iron citrate is commonly named component “A,” and the solution of potassium ferricyanide is then component “B.”
Components must be stored in a dark place, out of reach of children, and in tightly closed bottles. These light-sensitive emulsions are then mixed together in a ratio of 1:1 immediately prior to use.
As with almost any other photographic process, we can also many different formulas find in cyanotype. In this guide, we will learn only about the so-called “modern formula,” as it is the most popular among users, thanks to its easy preparation and good results. Several other formulas can be found online at http://unblinkingeye.com/Articles/cyano/cyano.html.
Before making the solutions, we have to read all the instructions and advice for working with the selected chemicals. We have to protect ourselves appropriately, prepare the working environment, and gather up all the necessary materials and accessories. We will need the following:
- A pair of gloves and other prescribed safety equipment
- Two plastic spoons
- Ammonium iron citrate
- Potassium ferricyanide
- Distilled water
- A precision or kitchen scale (this is only used for weighing photo chemicals)
- Two clean sheets of paper, size A5 (appr. 6 x 8 in)
- A small glass funnel
- Two brown-colored glass bottles
- Two labels for the bottles
- Formalin, which is a 37% solution of formaldehyde (HCHO) diluted in water (optional)
Prior to each production and use of solutions, it is best to read the instructions and warnings. Information on safety, the so-called MSDS (Material Safety Data Sheet), can be found online or in relevant manuals.
Making a modern formula emulsion
With cyanotype, this modern cyanotype formula is the most popular with users. It is composed of component A, i.e., a 20% solution of ammonium iron citrate, and component B, an 8% solution of potassium ferricyanide. For the production of 200 ml of the solution we will need the following:
- 20 g of ammonium iron citrate
- 8 g of potassium ferricyanide
- 200 ml of distilled water
- 2 drops of formalin (optional)
How to make the solution
- At the start of the work, we paste a sticker with data about the solutions on each of the two bottles.
- Into each bottle, we pour 100 ml of distilled water. The easiest way is to use the scale. A bottle with a funnel is placed on the precision scale (1), the scale is calibrated to the weight to 0 g, and 100 g of distilled water (2) is poured into each bottle.
- A folded sheet of paper, size A5, is placed on the precision scale, and the scale is again calibrated to 0 g and 20 g of ammonium iron citrate is added with a plastic spoon (3).
- Using the folded sheet of paper, we gently shake the ammonium iron citrate into the bottle that has already been filled with distilled water (4), then tightly close it with a cap and shake it until the chemical is completely dissolved in the distilled water.
- Over time, mold can form in the ammonium iron citrate, but this does not affect the quality of cyanotype. The mold can be removed by filtering the solution through a paper coffee filter. Mold can also be prevented, by adding two drops of formalin to the solution of component A (5). Since the formalin is extremely poisonous if inhaled, it is best to add it in an open area.
- The second solution is made in the same way as the first. A folded sheet of A5 paper is placed on the precision scale and 8 g of potassium ferricyanide is then poured on it (6).
- Then we have to carefully pour the chemical into a flask B (7), seal it tightly with a cap, and shake it until the chemical is completely dissolved in the distilled water.
- The bottles are then stored in a dark place. Both paper and spoons must be discarded in the appropriate place for waste disposal.
Formalin is toxic if ingested or inhaled, and will cause severe skin burns and eye damage if it comes in contact with skin or eyes. Prior to using the chemical, read the appropriate instructions and warnings. Wear appropriate protective equipment.
Paper for cyanotype
To produce photographs of great quality, it is very important to choose the right paper. Here are some hints about paper.
- We need to buy an extremely durable paper, which, after prolonged treatment in water, does not tear and does not dissolve in the water. The most suitable is watercolor paper or paper for the graphic arts.
- For the same reason, it is advisable to use thicker paper. The thinner the paper, the more likely it will tear in water.
- Another very important factor is the chemical structure of the paper, which greatly affects the stability of the photograph. Because we know almost nothing about the chemical structure of paper, it is best to test each paper. If you don’t want to learn from your own mistakes, through trial and error, it is better to use a paper recommended by other users.
- Most of the art papers have a “right” and “wrong” side. On more expensive papers, the “right” side is recognized by the watermark with the name of the manufacturer. If the text of the watermark is turned correctly, so the name can be read, then the right side of the paper is facing us. On the cheaper paper, the “right” side is usually smoother and its surface is better treated.
- There are papers with smooth or rough textures. Photographs on smooth paper will be quite sharp, while those on rough paper will be soft and almost dreamy.
- Among the properties of the paper, the absorbency of emulsion is also important. If the paper is too absorbent, the image will be blurred. And in the case of lower absorption, puddles of emulsion will accumulate and the photo will be unevenly exposed.
- In cyanotype, the structure of the paper is most important. Since cyanotype adheres very poorly to plastic materials, it is best to use a paper which is made of 100% or at least 50% cotton.
Paper samples on the next page are prepared with the same emulsion, exposed to the optimal, standard exposure time of the selected sample, and developed in the same way. Nevertheless, the results are not universally valid, as they depend also on the composition of the emulsion, the moisture, UV light, etc… The examples that follow are intended only for identifying the characteristics of the paper.
- Darkest color. In some papers, we will achieve a very dark color, for example, on Fabriano Artistico, Arches Watercolor Cold Press.
- A uniform distribution of color. While some of the papers uniformly soak in the light-sensitive solution, on others we will see quite visible patches. These are most noticeable in bright colors. For lighter photos, smooth paper is more suitable, since it is able to produce a clearer and more uniform drawing. On the other hand, rough paper, which produces a nice image in dark tones, may result in a rather disturbing structure in the light tones.
- White dots. Due to the different compositions and manufacturing techniques of the various papers, white dots may occur in the photograph. The cause of these dots can be the coarse structure of the paper (Arches Watercolor) or a chemical coating, which is not suitable for the technique of cyanotype.
- Tonal range. Similar to the paper in an analogous photography darkroom, some papers show more contrast in the resulting photographs (Fabriano Artistico or F5), and others less (Arches Aquarelle Grain Satin, CANSON Edition, etc…).
Light-sensitive chemicals used in almost all old photographic processes, including those used in cyanotype, are largely and almost only sensitive to sunlight or UV lamps. Because of this, the old masters of photography printed photos with the help of a contact printing frame. The process is carried out in such a way that the paper soaked with emulsion is covered with a negative film, compressed by means of the contact frame and placed in the sun. The negative, of course, has to be equal to the size of the final photo.
Although photograph printing was a seemingly simple matter in the past, the making of negatives was much more complicated. Enlarging a photograph was very difficult, and exposure and processing of negatives had to be carefully chosen and adapted for the selected emulsion. Manipulation of the photograph, in today’s terms, was almost impossible. Now, with the help of computers and software for processing digital photos, a photograph can be quickly manipulated. We can change its tonal values in just a few seconds; the size can be changed at will; etc…
Hardware and software
For making digital negatives, we need a personal computer. When we want to convert the analog film to a digital form, we will need a scanner. And for printing negatives, we usually use a inkjet printer.
For photograph processing, any program for digital photograph editing can be used. In this book, we will use the well-known Adobe Photoshop software.
Since the technique of cyanotype is quite simple and technically undemanding, digital negatives for it can be made from plain paper, from tracing paper (which was once used by technical draughtsman), or from overhead transparencies or transparent films that are designed for offset, silk or “alternative” photograph prints. Among these materials, there are, of course, quite big differences.
The range of tones printed on plain paper (1) is very small, so the very light and the darkest tones are hardly visible.
Negatives of photographs printed on tracing paper have a slightly better tonal value, but the image is rather blurry because of the greasiness of the paper (2).
Much better negatives are those printed on overhead transparencies (3), where we will notice significantly greater tonal values, but the very best are those printed on transparent films for offset printing and “alternative” photography (4).
Transparent films for “alternative” photography or offset printing are, of course, much more expensive than others, but allow us high-precision printing, due to their special coating, which is also capable of absorbing much more color from the ink jet printer. This, in turn, allows us to print negatives of much more contrast.
Making digital negatives
Since the description of the workflow for producing digital negatives using curves or color spaces (which must correspond to the various technical requirements of the photographic processes and of the selected material) is a bit too broad for this book, this chapter describes only a few basic procedures, with which we can also achieve largely high-quality tonal values in cyanotype.
If we want to create a digital negative, we need a black & white or color digital photograph of better quality.
- The photo is first converted to a 16-bit grayscale image (1).
- In the next step, the photo is digitally manipulated (2) so that it fits our aesthetic requirements. Most often, we increase the contrast of the photograph and sharpen it a bit.
- Since we are producing photographs which were made by old techniques using contact printing (without a photographic enlarger), we need to change the photograph size to the desired final size.
- The printing resolution of the photograph is usually set at 300 dpi or more.
- In the next step, the photograph is converted to a negative, using the appropriate command in the software (3).
- As we will place the emulsion of the negative onto an emulsion of the paper in contact printing (5), we have to mirror the image (4).
- Finally, the photograph is printed on suitable transparent material.
Unfortunately, the printed photograph will not have the same tonal values as the image we see on the computer screen, due to the different responses of the emulsions to various factors. If we want to adapt our digital photograph to a chosen photographic technique, a given printer, a type of paper, a chemical formula, etc.., we have to correct its tonal values. The easiest way to change those values is by the means of curves, which we will learn about in the following pages.
On the previous page, we described a simple procedure that allows us to make a digital negative. We have also mentioned the problem of tonal values, which may look great on the computer screen, but disastrous on the printed cyanotype. The reason for this is the varying sensitivity of emulsion, the different properties of paper, and the different clearness of transparent films; the type of printer and printer inks also greatly affect the photograph tone.
In cyanotype images printed with unprocessed negatives (1), we will frequently notice fusion of dark values into a single black surface (2).
The problem will be more easily understood if we look at a so-called grayscale step wedge, on which 21 different shades are printed. These range from completely white to a completely black color value.
The negative of a properly printed grayscale step wedge, which has evenly spaced values (3), produces similarly different values on exposed cyanotype (4). We can see that the white color has moved to another field and the lower half of the wedge has become evenly dark, without any transition (5). To sum up, only half of the total range of values is displayed on the printed cyanotype.
Our mission is to stretch this compressed area of cyanotype values (6) in such a way that it is fully displayed (8). This is done with a variety of methods, but the simplest way to make perfect cyanotype (9) is to use a curve (7) which will produce exactly the same values as on the original picture (1).
Making curves for a digital negative is just one of the many methods that can be used to achieve the correct tonal values on the photograph. This method is quite simple, but still too complex to be fully described in this book.
In this section, we have therefore focused only on the method by which a so-called “average” curve is applied to a digital negative. This curve is, of course, not intended for use with a specific combination of printer, transparent film, paper, UV light … but represents the combined, average tonal values of different printers, paper, transparencies, etc.
However, despite these generalizations, the “standard” curve can significantly improve the appearance of cyanotype prints.
For digital processing of photographs and negatives, we have used Adobe Photoshop software.
- Before we begin with the work, we have to download the “average” curve, which is named Std-cyan-1.acv. This can be found on the internet address www.petermrhar.com/alternative.
- In the next step, we have to convert the photograph to a 16-bit grayscale image by using the commands Image >; Mode > Grayscale.
- Then the photo is digitally processed (1).
- In the next step, we have to change the size of the photograph and its resolution.
- In the Adobe Photoshop program, curves are loaded through the commands Image > Adjustment > Curves.
- When the window Curves (2) is opened, we click the button Preset options and select the command Load preset (3).
- In the dialog box, we have to find and select the file Std-cyan-1.acv. The file is loaded with a click on the Load button.
- In the Curves dialog box, we will see the loaded curve (4). The curve is added to a photograph by clicking on the OK button. The appearance of the photograph, under the effect of the curve, changes considerably (5).
- Finally, the photograph is converted to a negative, then mirrored and printed on transparent film or some other transparent material.
When we print a photo that was previously corrected with the curve, we will notice a much finer and greater tonal range.
More about digital negatives and the use of a custom curves, which are the modern basis for old and alternative printing techniques, can be found in the book Easy Digital Negatives.