1 Under red lighting best quality writing paper is dipped in weak silver nitrate solution, followed by potassium iodide solution, and wiped dry.
2 One side is coated with an ‘exciting’ solution of gallic acid and silver nitrate, applied with a brush. The sensitised paper is then dried in front of the fire, and placed in a light-proof holder to take to the camera.
3 Exposure in the camera for about 1-3 min.
4 Development, in the same exciting solution as 2 but diluted to half strength.
5 Fixing in hyposulphite of soda, washing and drying.
6 Another sheet of paper is soaked in salt solution and wiped dry.
7 Under red light it is brushed over with silver chloride solution, and dried.
8 Pressed in tight face contact with the negative in printing frame, the paper is exposed to bright sunlight until it forms a strong brownish image (about 20 min).
9 The print is fixed, washed and dried.
PDF: Calotype process