Learn to perform the old photographic technique, exposing photosensitive emulsion in sunlight. Blueprint – cyanotype, or cyanotypi, is made with a kit consisting of two chemicals. It is not difficult to make cyanotypes, but it is challenging to master the technique to perfection. So do not expect to be able to manage your prints from day one.
What is a blueprint?
Blueprint is a photographic technique for duplicating a negative. Blueprint has been used primarily in architecture, where it was used for copying construction drawings. Over time, therefore, a blueprint has become synonymous with a technical drawing.
NOTE: However, the word is often used today about guides in general.
How does cyanotype work?
Two iron salts are used to make cyanotype blueprints: ammonium iron (III) citrate and potassium hexacyanoferrate (III).
The iron salts together make a chemical reaction when exposed to UV light and form iron ferrocyanide, also known as Prussian blue. The blue color is permanent but should not be exposed to alkaline material. It is the part of your imprint that has not been covered by material that will appear blue.
What can be blueprinted?
Any natural surface can be treated with the cyanotype chemicals, including:
- silk
- cotton
- wool
- hemp
- hear
- canvas
- paper
- leather
- tree
Materials for blueprint
You can choose to buy a so-called cyanotype kit or purchase the chemicals and mix them yourself. The mixing ratio is described in the kit.
- Chemicals
- Water
- Media to which print is to be transferred (e.g., watercolor paper)
- Sponge for applying the emulsion
- Bowl to mix in
- Spoon to mix with
- Glass plate to lay over the print while exposed to light
- A bathtub suitable for the paper to be covered in water
How to make cyanotype prints – step by step guide
There are two methods you can choose between. You can either buy paper prepared with cyanotype chemicals or mix and process the paper (or what you choose to print on) with the iron salts yourself.
If you print on your own paper, watercolor paper is best, as it must be able to withstand lying in the water.
- Preparations of the motif. For example, print a negative of the image you want to print (if you’re going to make a cyanotype an image). Most people choose to print on transparent material. You can also select clippings or other flat materials such as plants etc.
- Mix the two chemicals as prescribed in the instructions on your kit (some must be mixed with water as well)
- Apply the cyanotype chemicals to your chosen medium without exposing it to (too much) UV light. Let it dry
- Place the negative or object you want to print on top of the prepared paper and place a glass plate over it to hold things together.
- Expose in the sun or under a UV lamp. The surface becomes slightly copper-colored, and this is how you can see that the reaction has taken place. The exposure time can vary from seconds and up to 40 minutes but is typically between 10 and 20. Remove the glass and the negative (see the image examples under the heading exposure time)
- Develop the print by immersing the paper in water. You can experiment with how long it needs to be fixed in water – up to 15 minutes is typical.
- Dry the print by hanging it on, for example, a clothesline with a clamp
Exposure time
The difficulty with the blueprint is determining how long the print should be exposed using UV light. The sun’s content of UV rays varies from day to day, which means that many people choose artificial UV light for exposure.
The longer the cyanotype is exposed to UV, and the more UV light present, the darker an imprint occurs there.
Play with the development process
During the development process in water, the blue gets darker, but you can also try adding, for example, a few drops of oil or other liquids to the water after you have put the print in it. This will create different effects in the finished image.
The history of blueprint technology
Blueprint was invented in 1842 by the chemist John F. Herschel, a private friend of Anna Atkins’ family. Anna was an exciting woman, which you can read more about at the end of this guide. The technique was created to duplicate construction drawings, which was otherwise a significant job to get copied by hand drawing. Anna realized the applicability of the method in other subjects as well.
Today, the cyanotype technique is primarily used in the world of art, where the beautiful blue color stands alone in expressive works or is combined with other methods.
Anna Atkins and the world’s first photographic book illustrations
Anna Atkins was a pioneer in photography. She was born in 1799 as the daughter of John George Children, a scientist and member of the Royal Society. He was very supportive of her scientific interests at a time when women were otherwise not welcome in the subject.
Atkins was an avid artist in drawing, watercolor, lithography, and an enthusiastic botanist. She discovered that cyanotype provided an opportunity to reproduce botanical illustrations differently than the usual colored drawings.
In 1843, Atkins began work on producing the cyanotypes that would make up the Photographs of British Algae: Cyanotype Impressions. Watch the first volume of the impressive work online: Cyanotype of British Algae
It took her ten years to complete her work.
With the work, Anna Atkins produced the first photographically illustrated book ever, and she is also considered the first female photographer in the world.