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Sidero-Cupreatype / Discolouration Na2CO3

Sidero-Cupreatype / Discolouration Na2CO3

REF #62
White Grey brown Grey yellow
Ferric Ammonium Citrate [NH4]{y}[Fe{x}(C6H4O7)] sol. 20%
1
Potassium Ferricyanid K3[Fe(CN)6] sol. 8%
2
Ammonium copper citrate (NH₄)₂Cu(C₆H₅O₇)₂ sol. 20%
1
Sodium carbonate Na2CO3 sol. 10%
365nm

Operating procedure

Used for recolouring behind, particularly with tannins.

Make a normal sidero-cupreatype (sheet #3) with:
- 6 minutes exposure
- 30+30 seconds rinsing
Na2CO3 bath for 1 minute
Washing 30+30+30 seconds