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CYANOTYPE FORMULA
for coating on transparant 16mm film (formula by DICK SULLIVAN)

CHEMISTRY
Green ferric ammonium citrate 13,6 g
Potassium ferricyanide 4,6 g
Oxalic acid 0,5 g
Water 100 ml
Gelatin 13 g

PROCESS
1) Mixing [in Safe light]
Pour the water into a stainless steel photo developing tank (like a Kindermann)
Add cyanotype chemicals one at a time, stirring to dissolve
(check that the emulsion is free of un-dissolved crystals)
Slowly stir in gelatin
Dissolve cold (gelatin cakes in hot water)
Slowly heat to 120 F / 48 C stirring constantly till all gelatin is dissolved
Remove from heat as soon as it reaches 120 F / 48 C

2) Ready to Coat (with a soft brush, little sponge or whatever tool you like to coat clear 16mm film with). Clear on the subbing layer side.

3) Dry the coated film, preverable on a flat table.

4) Exposure in (full) sunlight between 5 and 10 min (much more when cloudy)
Expose until the contrast of the blue gel and the black of the print are equal, or until the emulsion stops reacting to light

5) Develop in cold water
Fill a developing tray with cold tap water (at least below 60 F/15 C but colder is better). Use ice if needed! If the water is to warm the gelatine will dissolve and the emulsion will come of the 16mm film.
Leave the film for at least 30 sec. in the water.
Refresh the (cold) water till all green is gone.

6) Dry the film thoroughly

7) Project!
Careful, the handmade emulsion is fragile
lab
Esther Urlus