This enabled lines to be more deeply bitten, prolonging the life of the plate in printing, and also greatly reducing the risk of "foul-biting", where acid gets through the ground to the plate where it is not intended to, producing spots or blotches on the image. Examples including printing ink, paint, spray paint, oil pastels, candle or bees wax, tacky vinyl or stickers, and permanent markers. Zinc produces more bubbles much more rapidly than copper and steel and some artists use this to produce interesting round bubble-like circles within their prints for a Milky Way effect. The "echoppe" works on the same principle that makes a fountain pen's line more attractive than a ballpoint's: The slight swelling variation caused by the natural movement of the hand "warms up" the line, and although hardly noticeable in any individual line, has a very attractive overall effect on the finished plate. Relief etching was invented by William Blake in about 1788, and he has been almost the only artist to use it in its original form.

Previously the risk of foul-biting had always been at the back of an etcher's mind, preventing too much time on a single plate that risked being ruined in the biting process. Freedom and Resistance in the Act of Engraving (or, Why Dürer Gave up on Etching)," Art in Print Vol.Hopfer was a craftsman who decorated armour in this way, and applied the method to printmaking, using iron plates (many of which still exist).

The traditional aquatint, which uses either powdered rosin or enamel spray paint, is replaced with an airbrush application of the acrylic polymer hard ground. This is the technique of letting the acid bite lightly over the whole plate, then stopping-out those parts of the work which the artist wishes to keep light in tone by covering them with ground before bathing the plate in acid again.Missed payments may affect your ability to use Clearpay in the future and your details may be passed onto a debt collection agency working on Clearpay's behalf. oil/tar based asphaltum [18] or bitumen as hard ground, although often bitumen is used to protect steel plates from rust and copper plates from aging. However, even if you’re familiar with the term “etching,” you might not know exactly what the process involves. The roughened surface of the relief permits considerable tonal range, and it is possible to attain a high relief that results in strongly embossed prints. They were made according to a technique of alkaline etching developed by the Harappans, and vast quantities of these beads were found in the archaeological sites of the Indus Valley civilization.