The E-Sylum:  Volume 10, Number 37, September 16, 2007, Article 10

DICK JOHNSON ON THE DEFINITION OF HIGH RELIEF

Dick Johnson writes: "Carl Honore brings forth some interesting
comments in regard to high relief on coins and medals in last week's
E-Sylum. 'High relief' in numismatics is not difficult to define,
but it is a sloppy and inexact term. It comes from sculpture where
it means relief projecting more than half from its background with
extensive undercutting.

"Such sculptural high relief is impossible to reproduce by die
striking. Coins and medals cannot be struck from relief models
with undercuts.  Period.  In fact, coin relief requires a bevel
on the sides of all detail and lettering of at least 5 degrees.
Anything less than 2½ degrees will always 'hang up' in the die
and not eject, less than 5 degrees it will sometimes hang up.

"What 'high relief' in coin making means is the highest possible
form of 'coin relief.' Coin relief is VERY LOW modulated relief
that forms the design that can be struck in a coining press with
one blow, and has a name in Italian, 'stiacciato.' Why Italian?
Because Italians named all forms of sculptural relief:

High relief (Italian 'alto-rilievo').
Medium relief ('mezzo-rilievo').
Low relief ('basso-rilievo').
Very low relief or coin relief ('stiacciato').
Hollow relief ('cavo-rilievo').
Intaglio or incuse relief ('intaglio rilievo').

"For medals any of the last four kinds of relief can be reproduced
and the term 'bas-relief' is a term used for all such medallic relief.
(The "s" is silent, it is pronounced BAA-relief).

"For the high relief on coins (that Carl talks about) this has to
be in the original model. Most mints prepare their models on a
'basin' – an oversize plaster base preformed with a slight basin
shape, upon which designs are made by building and shaping with
modeling clay or plasteline. Carl mentioned “concave fields.” The
base upon which models are prepared – with a basin shape ultimately
forming the coin's background – give opportunity for this high relief.

"The Franklin Mint demanded all models be prepared on such 'basins'
and would often furnish these to their modelers (because all their
work was struck on coining presses). But they demanded no relief
higher than 3/16-inch and whipped out a 'depth gauge' to test this
height on all incoming models. All artists creating models for a
series of medals were required to use the 'basin' required for that
series (for uniformity).

"Medallic companies do not have this requirement. They could prepare
their dies from any reasonable size or kind of bas-relief models.
Their models were prepared on 'background plates' – bases not
necessarily basin shaped. The background plate for medals can be
concave, flat, or even convex in contrast to the concave shape of
a basin. [In my video 'The Medal Maker' it shows Laura Gardin Fraser
making her own background plate of wood and shellacking it to give
it a nonporous surface.]

"Metal workers call this slight curve in a basin shape a 'camber'
and I have written about this previously in E-Sylum. If a camber is
not in the model a slight basin can be created, or increased, on a
modern die-engraving pantograph (like the Janvier). See
esylum_v07n11a10.html
"Carl's mention of Adolph A. Weinman's knowledge of coin and medal
making technology is absolutely correct. In addition to being a
highly creative designer he had been preparing bas-relief medallic
models – for medals, plaques, reliefs -- for two decades prior to
his 1916 Mercury dime and Liberty Walking half dollar. In fact, the
U.S. Mint actually struck his 1904 Louisiana Purchase Exposition
Award Medals in four varieties.

"Weinman was well versed in the technology involved. He had been a
friend of the Weils, Henri & Felix, founders of Medallic Art Company,
even attended classes at the National Academy of Design with Felix
years prior. He had access to their plant in New York City and, of
course, to their medallic knowledge. Imagine their conversations
exchanging technological knowledge together!

"Carl also mentions the problems of striking the Buffalo nickel. The
problem is known as 'congruent mass' where high relief exists on both
sides of a coin opposite each other. There is just not enough mass
in the blank for metal to flow into – and fill — all cavities in the
die in one strike. This can be solved by a pressman increasing the
striking pressure slightly. If not, it may mean remodeling the design
and cutting new dies (but I have no knowledge of this occurring in
recent years).

"Frankly, I believe what Carl is asking for in his request for high
relief coins is not high relief, as such, but rather, greater detail.
The remarkable advantage of coin and medal technology is its ability
to reproduce abundant detail in very small space. This is what gives
a coin or medal design its 'charm.'

"This detail is obtained by modeling oversize models with a simple
design that has extensive texture and detail. It is then reduced on
a die-engraving pantograph for dies to reproduce such minute detail
on all pieces struck from that die. Too many present day coin and
medal models lack this luxuriant detail."

  Wayne Homren, Editor

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