As far as I’m aware, this is the most sensitive cyanotype formula on the internet, and is just about usable for in-camera photography (ISO 0.0001): Sensitizer:(by mass) 0.05Ferric ammonium citrate 0.1Oxalic acid 0.85Water Developer:(by mass) 0.05Potassium Ferricyanide 0.01Citric acid 0.94Water The sensitizer solution must be protected from blue and UV light. The developer very slightly light sensitive, but realistically, it should be fine. Procedure: Spread the sensitizer on...
