|In preparation for the photogram workshop I'm teaching at the Louisville Visual Art Association on Sunday I had a little fun with chemistry. This process is from Photographer's Formulary and is the new improved Cyanotype chemical prep. You can do this in your house, just be sure to use safe handling procedures for the chemicals.|
This is not listed first on the instructions as the first step, but I do it first because it takes awhile to do completely. Finely grind 10g of potassium ferricyanide to a powder. *Wear protective gear! Gloves and a face mask!
|The crystals will start out red but turn light orange as in the photo above. If you think you are done grinding, go ahead and grid it some more! You need a very fine powder for it to dissolve quickly.|
|Heat 30 ml of distilled water to 120 degrees and add 30g of ferric ammonium oxalate, that will result in a green liquid when completely dissolved.|
Under safe-light or a very low watt (25) incandescent light, pour in a 10ml solution of ammonium dicromate. (Not pictured)
|While the solution is still warm (I keep my beaker in a pan of 120 degree water) pour in the fine ground potassium ferricyanide and stir until no red or orange crystals remain and green crystals begin to appear. Allow this solution to cool for 1 hour until just about room temperature.|
|When the solution has cooled strain the liquid through a filter (a standard coffee filter will do). A green sludge will remain on the filter which can be discarded. To the filtered liquid add 100ml of distilled water and put in a brown or dark colored bottle with a tight fitting lid. The solution can be painted on paper with a brush or use a glass coating rod. This chemical will last about 1 year in a tightly sealed and dark bottle.|