Etching (jewelry technique)

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With etching ( lat. : Radere scrape =, remove, remove) refers to artistic work techniques in which linear by scraping away a top layer or surface effects are obtained. Similar to the " etching " printing technique , in which one erases on a metal printing plate, the etching is also used directly as a jewelry technique by gilders . A layer of paint applied to the substrate (usually leaf metal such as bright gold or bright silver) is scraped off. The substrates for the etching are absolutely smooth surfaces, such as glass, foil, lacquer and leaf metal in gloss form themselves.

The technique of etching was also occasionally used in reverse glass painting , mainly to achieve graphic effects on a gold background. The gold leaf adhering to the back of the glass was worked on with an etching needle and then covered with black varnish. See the main article Églomisé . Virtuoso manufacturers of hollow glasses worked in a similar way, producing the so-called intermediate gold glasses in the 18th century, especially in Bohemia , in which two cut drinking vessels were nested and glued together so that the gold etching was enclosed between them.

The historical binding agent for an eraser color is glue glue. Casein-bound colors such as poster paint are also suitable for producing an eraser color. The Plaka eraser paint is easy to manufacture and does not require any special skill. Since this has a very high binding power (which is a disadvantage when etching) it is weakened somewhat with distilled water (for a longer shelf life, as the dirt in the tap water makes the paint easily perishable). However, this also inhibits the necessary opacity . Since powder pigments are unbound, they are ideally suited to give the eraser paint its necessary opacity. Care must be taken that the pigment is not too coarse in order not to damage the surface and not to provoke any breakouts. To make the eraser easier to erase, a little soap is added to the paint as a wetting agent.

The colorant is checked on a test piece that has the same properties as the main object. A soft hair brush is usually used to apply the finely sifted eraser color . After a short drying phase, the substrate under the paint is exposed. Church painters or gilders prefer to use a beech wood stick for etching because this wood is neither too soft nor too hard. The eraser should not be too pointed so as not to rub off the shiny gold from the poliment . If it is noticeable in retrospect that the eraser color is too strongly bound, the stick can be slightly moistened in order to be able to dissolve the color better (method according to P. Schütz). The workpiece should then dry out for about a day and then be coated with a clear lacquer ( zapon , shellac ).

literature

  • Hans Kellner: Gilding. Working with gold leaf. The most important techniques of poliment, oil, reverse glass and mordent gilding. With decorative techniques such as engraving, erasing, touchdown work and punching. Silver oxidation and luster detection . Callwey Georg DW GmbH, 2002, ISBN 3-766715313