Cyanotype / CuSO4-Na2S toning

Cyanotype / CuSO4-Na2S toning

REF #44
Potassium Ferricyanid K3[Fe(CN)6] sol. 8%
1
Ferric Ammonium Citrate [NH4]{y}[Fe{x}(C6H4O7)] sol. 20%
1
Sodium sulfide Na2S · 9 H2O sol. 2%
Copper sulfate CuSO4 sol. 20%
Ammonia solution NH3·H2O sol. 0.4%

Operating procedure

1. Make a basic cyanotype (6 min), with 30+30s rinsing, do not dry
2. Heat with a hairdryer
3. Na2S+NH3 bath for 30s
4. Basic rinsing (pH9) for 30 seconds
5. CuSO₄ bath for 5 min
6. Rinse for 30 seconds
After several days, it turns grey-yellow