Liver of Sulphur

The Liver of Sulphur darkens the bronze to a dull brown or black colour. The higher surfaces can then be rubbed back or polished to allow the natural bronze colour underneath to resurface.

In this video, Mark Longworth applies the Liver of Sulphur (Potassium Sulphide) to the crouching figure at the Bronze Age Sculpture Casting Foundry in London. Liver of Sulphur can also be applied cold but when applied hot, the chemical reaction is sped up and can be better controlled.

http://www.bronzeage.co.uk/
http://www.marklongworthart.com/