By Ash Zhang
History
Cyanotypes were invented by Sir John Herschel in 1842, relatively early compared to other techniques of photography. Initially, the process for cyanotypes relied heavily on photograms, one of the earliest forms of photography involving objects placed on chemically treated papers exposed to light. However, this process used silver-based chemicals, a costly and complicated chemical to work with. Through experimentation, cyanotypes were developed to use iron salts and sun exposure with a water wash, which was a much cheaper and easier process at the time.
This process was popularised by Anna Atkinson, a botanist and photographer who created the first photo book called “Photographs of British Age: Cyanotype Impressions”. It was released in 1843 and paved the way for the use of photography in scientific illustrations.
Classic blueprints were created using cyanotypes, containing a gorgeous Prussian blue that is instantly recognisable. Commercial use began in 1872 to copy plans and technical drawings as it was low cost and easy in terms of processing. This type of use was the dominant reprographic process until the 1940s.
Different types of cyanotypes
Putting objects onto the image is referred to as a photogram. This can also be replicated in a darkroom by placing objects on top of the paper and exposing it and is a very old method of making images.
Image negatives can be created by putting a thin sheet of plastic into a printer and reversing the black and white of an image on an editing software. This turns the whites into black and vice versa. This allows for the blacks not to be exposed to the sunlight, thus allowing them to remain white while the exposed areas turn a Prussian blue.
Personal Uses
This is a very simple process overall and a cool way to have your image in a format different to the usual ones. It is also fantastic printed onto a white T-shirt so you can customise and make your designs! Technically this works on most surfaces as well, so experiment as you will.
How to make a cyanotype, the surprisingly very easy step by step guide:
Mix the chemistry at the specified ratios according to the brand (Ammonium Ferric Citrate and Potassium Ferricyanide are often used)
Apply a thin layer onto a sheet of thick paper (inside without the presence of UV light, preferably using a foam brush for an even coat)
Dry the sheet of paper (which should turn into a chartreuse colour)
Put the objects or image negatives onto the piece of paper where you want it
Expose to UV light/sunlight until the colour turns to a dark brown-green. (For a dedicated UV light, it’ll be around 6-15 minutes depending on the strength of the light. Sunlight will take a significantly longer time.)
Wash with water until the image starts to show
Add a little bit of hydrogen peroxide to darken the colour faster
Continue washing until the image reaches the desirable colour
Dry and enjoy
Tips: Be careful to avoid extra chemistry on surfaces as it does stain surfaces.