Variations

The blueprint can be turned into a gray print by colouring it. It is best to do this after it has been fixed. Colouring is possible in a solution of tannic acid (web shop) of 1 gram per liter, but it is also possible with strong, cold, black tea. Rinse the blueprint in this solution for about ten minutes until the colouring has taken place.

Instead of Potassium ferricyanide red (T), Potassium ferrocyanide yellow (T) can be used, this gives a much darker colour with other contrasts.

There are several other options for further editing, we haven’t tried everything yet. Be aware that not everything works, don’t experiment with the most successful pieces, but make a lot of proofs.