VOCABULARY TERMS: PHOTOETCHED, PHOTOETCHING

Photoetched, Photoetching. Etching from a master that is a black and white print whose design is a drawing and lettering that is typeset or drawn. Photoetched medals are flat two-dimensional designs (biplanar), sometimes made of two separate thin disks soldered to form a two-sided medal. In other instances a thicker piece of sheet bronze (or white metal) is photochemically engraved on both sides for obverse and reverse designs, but this must be done in very close register. This process is mechanical form of relief etching.

For production runs the photoetching is not done one design at a time, but by step-and-repeat of a camera; the design is exposed to the treated surface of the metal where many of the same images are burned into one side of a large sheet of metal. This side is then acid etched. After washing and drying the sheet metal, the back side is then treated to be exposed to the camera and the same number of reverse designs are burned into the back side. It is then acid etched on that side. The medals are then blanked and edge treated. See acid etching.

These photoetched or acid etched medals are then given a patina to highlight their design. A black paint or enamel is applied to the crevices and incuse areas (covering up the rough acid etched surface). The black is in contrast to the higher, untreated surface which is left its natural color: brown of bronze, or the gray of white metal.

As the need for photoengraving for the graphic arts field has diminished (by 1960s, replaced by offset lithography), the equipment for photoetching began disappearing fast. It is only needed for the small relief signs and nameplates by the end of the 20th century.

Photoeteched medals. In 1964 the Stafford Manufacturing Company of Brooklyn made a number of designs of photoetched medals for sale at the New York World's Fair. These included John F. Kennedy, Abraham Lincoln and a medal for the Illinois Pavilion. There are a number of varieties (with and without facsimile signatures) and the Kennedy is Rochette number K- 64-12).

Photoetched model. The firm of J.R. Pinches, London, made models from photographs or black and white drawings. One was the Liberation Medal for the State of Israel, 1958 (SM-1). In his catalog of the firm's production, John Harvey Pinches briefly relates the technology. The obverse and reverse designs (by Otte Wallish from a Roman coin) was photoetched oversize into steel. This was then hand engraved intaglio to create modulated relief. This negative steel served as the pattern to pantographically cut striking dies in two sizes: 27mm for the gold and 38mm for the silver.

References:
NC10 {1973} Haffner, p 158.
O42 {1987} Pinches, p 257.

To read the complete entry on the Newman Numismatic Portal, see:
Photoetched, Photoetching (https://nnp.wustl.edu/library/dictionarydetail/516478)

	NBS (coinbooks.org) Web