Carborundum is a powdered mineral which can be mixed with glue to form a paste. Several tones can be mixed by adding more or less glue. This paste can then be painted onto a clean de-greased aluminium or plastic plate. Lines can be drawn or scraped back into the carborundum. This is a very fast and painterly way to make a plate. Once the glue is dry the plate can be inked up and run through an etching press with damp paper. This process allows one to work on a large scale as aluminium is inexpensive and also portable being lightweight. I frequently take large aluminium plates outdoors and work on them en plein air.