Operating procedure

1. Make a basic cyanotype (6 min), with 30+30s rinsing, do not dry
2. DMDTC bath for 40s
3. Rinse for 30+30+30 seconds
4. Pb(NO3)2 bath for 2 min
5. Rinse for 30+30+30 seconds

The reverse reaction (lead nitrate first) gives a much better result.