Mixing 12.5˙ baume Ferric Chloride for Soy Wax/Litho Ink Soft Ground

Baume Hydrometer (0-50 range)
Tall beaker – plastic or glass
Ferric Chloride Solution – 42˙ Baume
Horizontal tray


For this process you will be diluting a small amount of Ferric Chloride with water to reach 12.5˙ Baume. This solution consists of two parts FerricChloride to eight parts water.

1. Measure 200 ML of liquid Ferric Chloride into a tall beaker (be sure to add ferric before

2. In the same beaker, add room temperature water until the total mixture reaches 800 ML

3. Place Baume hydrometer into beaker to measure the strength of the mordant, which should
read at 12.5˙ Baume

4. If solution is too weak, add a trace amount of ferric until desirable strength is reached

5. If solution is to strong, add a trace amount of water until desirable strength is reached

6. Once you have reached your desired strength, pour solution into a horizontal tray placed on a stable surface (ideally a flat table or sink)

After etching the soy wax softground in the tray, the mordant can be returned to a plastic safety bottle and stored for re-use.

Mixing Soy Wax Litho Ink Soft Ground and test plates