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Some owners like to see a patina on copper or brass, others like
their treasures with a glowing deep polish that smiles back at them each time
they are admired. It is difficult to generalise but feedback suggests that in
the UK the general preference is for most items to be kept polished unless they
are very old whereas in the USA there is a stronger preference to see a patina
form on more recent items. This is perhaps the reverse of the situation with
pewter where it is very rarely ever polished in the UK. The market for
pre-patination on new items is also stronger in the USA.
A genuine patina will have been built up over many years and be
much appreciated by many owners. As copper oxidises it also picks extra
compounds up from the atmosphere in which it is exposed. These compounds give
rise to the composition of the patina including carbonate and sulphide as well
as a mixture of at least two of the three possible oxides of copper. Occasional
waxing of the patina may also have improved its appearance.
Patinated
brass products were offered by many manufacturers, giving a range of possible
permanent finishes. They are produced by a chemical colouring treatment that is
protected by a special durable lacquer. Most companies were very careful
not to reveal the process used but commercial treatments are available from
suppliers of metal finishing products.
Colour
Descriptions
The following descriptions
are included in the 1935 catalogue issued by W A Hudson & Sons. Other makers
might differ.
Antique
Copper (also Ant.Cop, A/C, Oxidised Copper and Ox Cop.)
A general term used to
indicated a dull matt copper finish with areas of darker relief which give
emphasis to parts of the product.
B.M.A.
(Bronze Metal Antique)
A greeny fawn colour
obtained by baking solid bronze metal in a damp atmosphere. The same colour can
also be obtained by oxidising brass.
Bronzed
or Oxidised
Vague terms when used
commercially.
Copper
Bronzed and Relieved (C. B. & R.)
A bright copper finish with
dark or black shading.
Florentine (also Flor., Florentine Bronzed) .
A uniform chocolate
colour.
Steel
Oxidised (Steel Bronzed, Ox. Steel)
A uniform dark blue grey
finish on brass, not to be confused with oxidising on steel.
A classic reference book summarising possible treatments was
originally published by the Arts Council, London in 1981:
‘The Colouring,
Bronzing and Patination of Metals’, R Hughes and M Rowe, Thames and
Hudson, 2nd Edn. 1991, 372pp. ISBN
0 500 01501 5.
A manual for fine metalworkers, sculptors and designers.
This
describes hundreds of tested techniques for making surface finish colours,
colour illustrations, 404 references.
Patinated
brass products were offered by William Tonks & Co. The special
colour page shown below was inserted in the front of their 1939 catalogue and
shows finishes named:
(1) Antique Coppered, (2) Nut Brown, (3) Satin Brass,
(4) Florentine Bronze, (5) Bronze Metal Antique (BMA) and (6) Silver Grey.
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