Cyanotype is a Greek Word meaning " dark blue impression " this process undeniably is the easiest and the least expensive of the various Alt- Processes. Besides the chemicals mentioned all you really need is a negative or an object the same size of the image intended for printing and consistent sunlight, the ideal source for exposure available to you locally and free …… {Karachi - Pakistan}

Its invention is credited to Sir John Herschel {1842} who used it as a method for copying his elaborate notes. This process is a member of the family of iron salt process that includes the Kallitype the Palladium print and Platinotype.

THE FORMULA

While on the search came across several Cyanotype Process formulas, don't claim to have tried all but the few experimented with the intention to find something with intense blues and a reasonable long shelf storage life. The formula finally selected worked well with a German Made paper called Schoellershammer 9 HF Feinkorn (Fine Grain) 220 G, which was easily available at the local art materials supply shops with an affordable price tag. This formula gave me intense blues on this particular paper and the long shelf life suited me just fine.

Solution A
::. 1.25 grams oxalic acid
::. 67.5 grams ferric ammonium citrate
::. 250 cc Distilled water

Solution B
::. 1.25 grams oxalic acid
::. 22.5 grams potassium ferricyanide
::. 0.5 grams ammonium dichromate
::. 250 cc Distilled water

PLEASE NOTE ::.

::. Mix solution A & B separately and store in separate Amber (dark brown) colored airtight bottles. If prevented from contamination this formula will last about 4 months.
::. Mix the chemicals about 2 days before actually using them.
::. 250 cc (cubic centimeters) = 8.45 fl oz (fluid ounces) / fl ounces x 31.25 = ml
::. Ferric ammonium citrate comes in green and brown varieties. The green is more sensitive use this instead of the brown.
::. Oxalic acid is a poison, which can be ingested directly through your skin into your blood stream. Also read the notes on how to handle chemicals safely.

MIXING THE CHEMICALS AND PREPARING THE PAPER ::.

Just before use mix equal parts A & B. Coat the mixed sensitizer on acid free watercolor paper (test various papers before the final selection) with a metal free brush (I use a normal brush and cover the metal part of it with a plastic tape to prevent the metal from reaching the formula) or a sponge, in a subdued light area (UV Free).

Spread a fine coat of the mixture on to the Paper. This coated paper will retain. Maximum sensitivity for about 4 hours after it has dried and about half as long if the weather is humid (summer). The surface appears greenish yellow when it is totally dry (Hair dryer can be used to speed up the drying). In case there is any mixed chemical remaining don't store it but drain it since once mixed they are short lived (sensitivity level) depending on the weather, its good for use from a couple of hours to nearly a day.

PLEASE NOTE ::.

Remember not to re coat an area, which has started to dry since it would negate the level of sensitivity in that area.

THE EXPOSURE AND THE WASHING ::.

Once the coated paper has dried, expose the enlarged negative in a contact frame or with a heavy enough glass that is slightly larger than selected final print size & that gives you a good contact with the sensitized paper. Exposure times should be decided with test prints since they can vary and depend on the intensity of the light source and the negative density. Wash the exposed print in running water 5 to 10 minutes or till the water clears of Color. Over washing can bleach the print so be careful.

PLEASE NOTE ::.

Test the water for the level of alkaline, pH8 or higher will bleach the image.

DISCLAIMER ::.

It is the responsibility of the user of toxic chemicals to take proper precautions to avoid intake. The author cannot accept liability for any injury, sickness, or damage resulting from these processes.