Copper Sulphate as an etchant for zinc has been used for a long time. Some suggest Goya used it in his etching studio, but this cannot be verified. In the 1990’s when much attention was being turned to toxicity in print studios, Cedric Green and Nik Semenoff utilised it as a safer alternative to nitric acid. Latterly Friedhard Kiekeben, inventor of the Edinburgh Etch, progressed it into the Saline Sulphate Etch (© F.K. 2002) for use on zinc, aluminium and steel.

Copper sulphate solution alone will etch zinc and the addition of sodium chloride (table salt) improves the performance and longevity of the etching solution. For more information, please take a look at our PDF guide 'Etching Zinc with Copper Sulphate'.