Calotype process



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.


Positive print

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