Cuprotype (Paterson)

Cuprotype (Paterson)

REF #53
Ferric Ammonium Citrate [NH4]{y}[Fe{x}(C6H4O7)] sol. 20%
1
Copper sulfate CuSO4 sol. 10%
1
Potassium Ferricyanid K3[Fe(CN)6] sol. 2%
Sodium thiosulfate Na2S2O3 sol. 10%
1

Operating procedure

I found several recipes, here is the one I used:

1. Mix equal parts citrate, copper sulphate and thiosulphate.
2. Spread on the paper.
3. Leave to dry for 30 minutes.
4. Expose (10 minutes).
5. Rinse for 2 minutes (neutral water).
6. Ferricyanide bath for 2 minutes.
7. Rinse 3 times for 30 seconds.