Salt & Cooper Sulphate Etching on Aluminium (Please see Summer school for dates & costs)

Etching using salt and copper sulphate, a safer mordant that has proven very successful for etching onto aluminium and zinc, giving both line and tonal values without the use of aquatint. This is the only method for etching aluminium that really works.

The aim of this course is to learn the basic technique of etching with salt etch. The aluminium plate is prepared by smoothing the edges of the plate by filing or using course and smooth sand papers. Degreasing the plate to help the integrity of the ground, protecting parts of the plate not to be etched. The same wax grounds can be used as for conventional etching: an ink-based ground can also be used but takes a while to dry. Once the plate has been coated with the required ground, an image is drawn into the ground using an etching needle. The back of the plate should then be covered with an acid resist tape and submerged into the copper sulphate and salt bath. This will instantly start to etch and lift the surface of the aluminium. A copper residue will appear on the surface of the bath in the form of the drawing, indicating that the mordant is working.