By TooPink
Cyanotypes are a historical photographic process first developed in the mid 1800s. They were used to make early blueprints, and were the printing method used by Anna Atkins, one of the earliest female photographers, in the world’s first photo-illustrated book, Photographs of British Algae: Cyanotype Impressions. The cyanotype process is based on the combination of two chemicals, ferric ammonium citrate and potassium ferricyanide, which when exposed to light undergo a chemical reaction that produces ferric ferrocyanide, also called Prussian Blue.
Personally, I prefer Jacquard brand chemicals, I find they print a deep blue and its popularity means chemicals aren’t aging on store shelves for too long. To make your own cyanotype at home, fill both bottles with the cleanest water you can find (distilled is ideal), shake vigorously, and leave overnight. The next day, prepare your work surface in a dimly lit room and cover in plastic wrap to prevent staining. Agitate the chemicals and combine equal parts of Part A and B to a non-foodsafe container, using a scale to ensure accuracy. Mix well until combined and use a paintbrush or foam brush to apply the chemicals to your surface.
Cyanotypes can be made on many materials including paper, fabrics, clothing, leaves, and even rocks—as long as the surface is porous, you can make a cyanotype. If using paper, choose a sturdy, high quality watercolour paper. If using fabric, natural materials that absorb liquid well are best, as artificial fabrics run the risk of not bonding with the chemicals, causing your print to fade while rinsing. Coat your surface evenly and thinly, then leave to dry in a dark place. Be careful—cyanotypes need to dry over many hours, so even a small amount of light can cause fogging.
1. Coated paper
Once the cyanotypes are dry, prepare the objects you want to print. Cyanotypes are a negative process, meaning anything exposed to light will turn blue, and anything blocked from light will remain white.
2. Paper with negatives
If your object is something flat, like a pressed flower or a piece of film, place a sheet of glass on top while exposing the print so it doesn’t move during the exposure. Find a sunny spot outside and quickly place your film, flowers, or objects on top of the completely dry coated cyanotype. Avoid moving the print, as that will affect the clarity of the photo.
3. Paper with negatives and glass sheet
Leave the print in full sun for 10 to 30 minutes (depending on the UV index of the day). You’ll know when it’s fully exposed when the surface turns slightly brown or gold, and remember it is always better to over-expose than under-expose! Remove the objects and quickly take your print out of the sun and into a dimly-lit sink or water source.
4. Exposed Print
Rinse it gently under cold running water for 5 to 10 minutes, until no yellow tint remains in the white spots. As you rinse your cyanotype, you’ll see the details start to come through, and the colour initially shift to light cyan or purple, eventually darkening to prussian blue as time passes.
An extra optional step is to soak the print in a mixture of water and hydrogen peroxide. Like magic, you’ll see the colour darken significantly. If not using peroxide, your print will still darken over the course of a few days.
Once the print is completely dry, you’re done!
5. Washed Print
Cyanotypes are a fairly permanent print, especially when stored in a cool, dry place and not in direct sunlight. Cyanotype clothing may fade faster due to regular washing, so make sure you always wash them gently in cold water and hang to dry.