While etching has become something of a lost art-form, it's one of the great, classic fine art printing processes, beloved of Picasso, Matisse, Modigliani, Hockney, Jim Dine and most of the major contemporary artists. To create an etching, a highly-polished copper plate is first cleaned with caustic soda and dilute nitric acid. The plate is held face up over a gas or oil burner to melt the etching "ground" which is a thin bitumen coating rubbed perfectly smoothly and evenly over the surface of the copper plate. The ground is blackened so that, when the design is drawn on the copper with a needle point. the metallic line will shine through. The plate preparation requires considerable experience and skill to produce etchings in this traditional way. Next, the outline of the design is transferred to the blackened ground. An effective method of achieving this transfer is to blacken a sheet of tissue paper with soft lead pencil like a carbon copy paper. This is placed over the plate and the pencil design for the etching pinned over it and traced lightly with the etching needle. As the hand must never touch the ground, a support is placed across the plate. It is a very delicate technique and the design is often drawn under a magnifying glass, leading to an extremely cramped posture for the etcher. There are various methods of needling a plate, one method is to etch out the fine grey tones first, and by a series of re-etching to add the half-tones and blacks. The etching itself is done by placing the plate in a solution of dilute nitric acid which bites only into the parts of the copper exposed by the needling. This is the most anxious moment and is carefully timed. If the artist miscalculates he may either under-etch or over-etch and thereby ruin the result of a week or more of careful work. No amount of experience can give him full assurance over his timing. He may have got a hard copper plate which etches slowly or a soft one which etches too quickly. The acid is constantly weakening as it works on the plate, and the artist must keep adding fresh acid to try and keep it at an even strength. Having no means of testing its strength, he must trust luck and instinct on equal terms to get the result he wants. Finally, the artist wipes off the ground and takes a proof of the plate. If the result is a failure he has no resource but to discard the plate and start all over again with a fresh one. If the result of the first proofing is satisfactory he re-cleans and regrounds the plate and sets about working on the next section to be etched, and so on, proofing and re-grounding until the plate is finally completed. which may take a couple of months.