[tutorial] Basics of Cyanotyping

Introduction

A very interesting and easy to do method of printmaking is the photography-based process of
cyanotyping. The Material needed is much cheaper than for example for screen printing and it is
possible to achieve decent results with varying dark tones. The disadvantage of this method is, as the
name suggests, that the resulting copies will be monochromatic, namely in a blue tone (Prussian blue
or Berlin blue).

Material

  • Paper, best is watercolor paper
    (I tested different kinds of paper here)
  • Transfer film (Inkjet/Laser overhead projection film, or screen print template film)
  • Potassium ferricyanide
  • Ammonium ferric citrate, with at least 18% Iron content (= green color)
    OR Ferric ammonium oxalate (differences see here)
  • Brush
  • Syringe without needle OR plastic Pasteur pipette
    Optional:
  • UV light
  • Glass Plate

Process

Make Emulsion

Firstly, you need to mix the two salt solutions for the photosensitive emulsion:
Component 1: 8% Potassium ferricyanide solution (for example 4g in 50 mL Water)
Component 2: 20% Ammonium ferric citrate OR 30% Ferric ammonium oxalate.
Its best to used deionized or distilled water, but regular tap water works as well.
These solutions are storable for a long time.
The best methos is to keep them dark and cool, to prevent molding and bleaching, since both,
Ammonium ferric citrate and Ferric ammonium oxalate are light sensitive, and Ammonium ferric
citrate is a good base for mold to grow on.

Attention: Potassium ferricyanide is toxic for aquatic life, and will produce Hydrogen cyanide, when it comes in contact with acids. The formation of dust should be avoided.
As all Oxalates, Ferric ammonium oxalate is toxic when swallowed or when it comes in contact with the skin. Both these chemicals should be handled with care. Its best to wear gloves when working with them.

Coat paper

Directly before you want to make a cyanotype, mix both components of the emulsion with a Pasteur
pipette or a syringe without needle. I use a small plastic bowl to mix both components. Only a small
volume of both components is needed. About 1.0 mL of each is enough to cover a whole A4 sheet.
Cover the desired sheet of paper thinly with the emulsion, using a brush. I use a cheap synthetic bristle
brush for that task. Depending on the paper you are using, it could be that the paper will start to buckle.
To avoid that, the paper can be fixed on a firm underground (Cardboard, tabletop, etc.) with some
washi tape.
While the paper is drying, you can prepare the template.

Attention: From here on the paper should be protected from direct, or strong indirect sun light. Regular lamps are not a big problem.
The dried paper can be stored for a while in a dark, dry place.

Prepare negative

To copy an image in cyanotype, you need to create a template. This will be a greyscale version of the
original image with inverted colors (negative). This negative needs to be printed to a transparent film.
For me it made neither a difference if I used printable transparent overhead projection film, or
expensive screen print transfer film, nor if I used an inkjet or laser printer.

Exposure

When the paper has dried, the interesting part starts. Place the template on top of the paper and fix it
(I use a glass plate from an old picture frame for that). Now expose the paper with the template on top
to sunlight or artificial UV light (I built an UV box for that. Click here to see how). It can be tricky
to figure out the perfect exposure time, especially when you work with natural sun light. But the
exposure time does not only depend on the power of the UV light, but also on the type of paper, the
type of emulsion, the thickness of the emulsion layer and also which type of transfer film is used
(probably also other factors).
When the paper turns dark blue on the not covered (clear) parts below the film, it is time to stop the
reaction. It might take you a few tries to find the perfect time point.

Washing

To stop the reaction, wash the paper in a tray, sink or under running water. Move the paper around a
bit, by rocking the tray or just by grabbing it and moving it trough the sink, etc. when all the not reacted,
yellow residue is gone, the washing is done. The exposed parts of the emulsion turned into Prussian
blue, which is insoluble in water. However, when the exposure time was too short, it will not stick to
the paper and wash out as well. Anyways, a bit or the Prussian blue will always wash out.
After washing the paper can be dried. I just stick them to my kitchen tiles for that. But you can also put
them in a plastic tray, or on the windowsill, or wherever.
When completely dry, the paper may be wrinkled. I place them under the glass plate again, with a
heavy book on top, to straighten them again. You can do that even, when the paper is still drying, to
safe some time.
After this the cyanotype is finally done, and you can admire your result.

Sources

https://de.wikipedia.org/wiki/Cyanotypie
https://en.wikipedia.org/wiki/Cyanotype
https://www.pixartprinting.co.uk/blog/guide-to-cyanotype/
https://parallaxphotographic.coop/how-to-make-cyanotypes/
https://www.sciencecompany.com/The-Cyanotype-Process.aspx
https://wp.radiertechniken.de/edeldruckverfahren-ii/cyanotypie/


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