Alternative Process: Cyanotypes
By Amanda Tarlau
Cyanotypes are another type of "Sunprint" in that the final image appears only with the aid of ultra-violet, or sun, light. The colours can range in their final metamorphose from pale to deep blue tones and everything in between. As with Van Dyke printing, the properly exposed and processed print will be permanent and archivally sound.
Originally, Cyanotypes (called "ferro prussiate") were used in conjunction with scientific recordings of mathematical tables, a diverse range of plant specimens and architectural structures. In fact, the first woman photographer, Anna Atkins, used Cyanotypes to print "Cyanotypes of British and Foreign Flowering Plants and Ferns" and was the very first book of printed photographs and text.
Cyanotype processing involves two stock solutions which need to be kept separate from eachother in dark glass bottles until required for coating. Stock Solution "A" uses Ferric Ammonium citrate Stock Solution "B" uses Potassium Ferricyanide Both of these chemicals are very toxic and care for yourself and the environment muct be taken at all times. When handling the chemicals, wear protective clothing and gloves, plus a dust mask when handling the powder form. Always work in a well ventilated area, no matter what process you are using. Dispose of excess chemicals by absorbing them into kitty litter, inside a plastic garbage bag and dispose of it in an outside garbage bin.
OK! Enough of that....what you do to start making blueprints....
STOCK SOLUTION A: Ferric ammounium citrate 90g distilled water 8 fl oz (124ml)
Adjust water temperature to 75 degrees F (23.8C). Using a funnel, pour 90g (124ml) ferric ammonium citrate into a clean glass beaker. While stirring, add enough water to make 8fl oz (250ml) of solution. Stir until dissolved throughly and pour into a labeled brown bottle.
STOCK SOLUTION B: Potassium Ferricyanide 50g distilled water 8 fl oz (124ml)
Adjust water temperature to 75 degrees F (23.8C). Using a funnel, pour 50g (65ml) Potassium Ferricyanide into a clean glass beaker. While stirring, add enough water to make 8fl oz (250ml) of solution. Stir until dissolved throughly and pour into a labeled brown bottle. Both solutions should last several months, and longer sometimes, if kept in tightly sealed containers and in a dark, cool cupboard. Make sure you keep these bottles clearly labeled and away from animals and children.
To use the solutions, shake each bottle then mix together 1oz (29ml) of both A & B together in a glass or ceramic bowl. This will coat around eight 8x10 in sheets of paper (any type of thick printmaking/drawing paper: Strathmores, Reeves, Stonehenge etc). Dip a wide haired or foam brush in the mixture and apply a small amount to the paper, coating the yellowish mixture evenly in long strokes to cover the area needed. Dry by a cool fan or hairdryer or lay flat until dry.
To expose the paper, place it on a backing board and cover it with the negative you have made to the same size as the paper. Sandwich it all together with a sheet of glass and clamp it with bulldog clips. PLace the frame under direct sunlight or another strong ultra violet source. The exposure times will vary from around 5 minutes to half an hour or longer depending on the level of light. You will be able to see when the emulsion is ready when it changes colour from yellowish green to blue/green to bright blue.
To develop the paper, simply remove it from the frame and hose it in a sink with cool water until the rinsing water is clear. You can then intensify the print by making a brightening solution with 2 capfuls of bleach to 2L of water and rock the print in a tray of it until the image turns a deeper blue. Wash the print throughly for 10 minutes, blot dry and hang on a clothesline or use a fan or hair dryer.
The process itself is very very simple and the results are strikingly beautiful. As with most alternative proceses you can experiment and combine processes such a Van Dyke and Cyanotype, although print the cyanotype first or the blueprint will obscure the print underneath. You may also like to try and experiment with placing objects such as ferns etc on top of the emulsion...the variations are unlimted.
If you have any questions or feedback email me at firstname.lastname@example.org