Copper in Art: A History

This section covers the historic use of copper and copper alloys in a number of civilizations over the centuries. It also discusses the
historical techniques used to create works or art, and gives some indication of how these have evolved over time.

A. Overview of copper history
B. Historical methods of making bronze sculpture
C. Historical use of these processes around the world

A. Overview of Copper History

The use of pure copper and its alloys goes far back in time. The casting of metal was common in the Near East. By 3500 B.C. Ancient Egypt
used bronze for statues long before Europe entered its Bronze Age. Bronze was also used for statues in ancient China and Thailand.

Ancient Greece and Rome took bronze statuary to new artistic heights. The island of Cyprus was a major source of copper for the Near East, Egypt and the Mediterranean.

The Greek name for Cyprus is Kupros and the word copper comes from this word. Copper and bronze statues were melted down and
reused, particularly by the Romans.

Copper and bronze sculpture was produced in Africa around the 9th century and in the Americas since pre-Columbian times. In Italy during
the Renaissance, bronze sculpture had a revival. France experienced a boom in bronze sculpture in the mid 1800s. The American states
began to be interested in bronze sculpture starting at this time.


B. Historical Methods of Making Bronze Sculpture

There have been four main methods of making bronzes throughout history:

1. piece-mould casting
2. hammered manufacture
3. lost-wax casting
4. sand cast


1. Piece-mould Casting

This method is thought to be the only one that was used in China from about 2000 B.C. to the end of the Shang dynasty around 1050 B.C.
In this method, a model is made of the object to be cast, and a clay mould is taken of the model. The mould is then cut in sections to release
the model, and the sections are reassembled after firing to form the mould for casting. If the object to be cast is a pot or bowl, a core has to
be placed inside the mould to form the cavity.


2. Hammered Manufacture

The earliest large Greek bronze statues had very simple forms because they were made of hammered sheets of metal that were attached
to each other with rivets. These sheets were often decorated by being hammered over wooden forms to produce relief details, or by
being cut into, using a technique known as tracing.


3. Lost-wax Casting

By 500 to 480 B.C., hammered manufacture was replaced in Greece by lost-wax casting.

There are three ways to do lost-wax casting:

a. solid lost-wax casting
b. hollow lost-wax casting by the direct process
c. hollow lost-wax casting by the indirect process


a. Solid Lost-Wax Casting

This is suitable for small figures. This process requires a wax model to be covered with clay and heated to melt out the wax. Bronze is then poured into the clay mould. When the bronze is hard, the clay model is broken off to reveal a solid bronze.


b. Hollow Lost-Wax Casting by the Direct Process

First, a clay core of the approximate size and shape of the planned statue is made.

If it is a large statue, an armature of iron rods may be used to stabilize the core. The clay core is coated with wax and vents are added to
let the molten metal flow in. The wax layer is covered with clay. The model is heated to remove the wax and create a hollow space. Bronze
is then poured into this space and cooled. The clay is broken off to reveal the sculpture, ready to be finished.


c. Hollow Lost-Wax Casting by the Indirect Process

Most of the large ancient Greek and Roman bronzes were made using this method. The original master model is not lost in this process, so
it is possible to make a series of the same statue.

First, a clay model of the statue is made. A mould of clay or plaster is then made around the model, in sections that can be taken off. When
dry, this clay mould is taken off, reassembled and put together. Beeswax is then applied to the inside of the clay mould. When the wax is
hard, the clay mould is removed and the wax model is checked for quality of detail. Corrections can be made at this stage.

Channels and vents are then attached and the whole is covered with clay. The clay is heated and the wax poured out. Bronze is then
poured in and left to cool. The clay mould is broken open to reveal the cast bronze statue. The pouring channels are removed and the
separately cast parts are then joined together. The Greek and Roman bronze workers are acknowledged for their great technical skill in
making these joins.


4. Sand Cast Method

During the 19th century, most of the bronze sculptures cast in France were made using this method. This method has been used since
1818. It requires the original clay or wax model to be cut into separate pieces. This destroys the original.

The pieces of the original are covered in slurry and dried. This mould is taken off the original parts. A bronze master model is then poured
into the moulds. This master model will be used for the bronze edition.

The separate parts of the bronze master model are pressed into large casting sand blocks.

A second sand block is pressed on top of the first one. The blocks are separated and the bronze master parts are removed, leaving their
imprints in the sand. Channels and vents are cut into the sand for the molten bronze to flow along and for gases to escape. The sand blocks
are bound together and molten bronze is poured into the mold.

Once cool, the blocks are separated and the bronze parts are taken out of the sand. The bronze-filled channels and vents are sawn off.
The bronze parts of the sculpture are put together with pins or bolts.

The master model can be used to make 15 to 20 casts before it starts to lose sharpness of detail and needs to be hand chiselled to renew
detail. This process produces many bronzes fairly quickly.


C. Historical Use of These Processes Around the World

The following places are known for copper and bronze work through history:

  • Near East
  • Egypt
  • Cyprus
  • Minoan Crete
  • China
  • Ancient Greece
  • Ancient Rome
  • Thailand
  • West Africa
  • Renaissance Italy
  • Americas
  • France
  • United States

Near East

Solid casting was established here by 3500 B.C. Bronze sculptures have been found in the ruins of ancient cities in Mesopotamia and Sumer.


Egypt

From the late Old Kingdom (c. 2420 B.C.) through the Greco-Roman period, most large-scale bronzes were made using the hollow lost-wax
cast method, some with a clay core inside the sculpture. Some statues were made with the hammered technique. Solid cast pieces were
simple in form and had no clay armature.


Cyprus

Pure copper was first used from 4,000 B.C. to make tools. Tin had to be imported to make bronze. It is thought that tin bronzes were made
on Cyprus at the beginning of 2000 B.C. In the 1900s B.C., Cyprus is noted for the first time in Near Eastern records as a copper producer
with the name of Alasia. Cyprus was an important source of copper for the Near East and Egypt for most of 2000 to 1000 B.C., in what is
called the Bronze Age. The word "copper" comes from Kupros, which the Greeks called the island.

On Cyprus, copper and bronze work was done on a limited scale in the Early and Middle Bronze Ages, to produce tools, weapons, pins &
razors. There was more metalworking in the Late Bronze Age. Many sites have revealed copper smelting. Few examples of bronzes
survive from 1450 B.C. to late 1300s because they were likely melted and reused.

A shipwreck was discovered with 10 tonnes (9 tons) of copper from Cyprus, that sank near Turkey in the late 1400s B.C. This is proof of
Cyprus being a major supplier of copper in trade. By the end of the late Bronze Age, bronzework from Cyprus was some of the best in the eastern Mediterranean.


Minoan Crete 2000 B.C. to 1100 B.C

From about 2000 to 1450 B.C., in Minoan Crete, there was thriving trade in tin, copper and many other materials, with other Mediterranean
cultures. Cretan Minoans imported tin and copper and developed great skills in working with bronze. Minoan culture on Crete was in serious decline by about 1100 B.C.


China

Their Bronze Age went from around 2000 B.C. through the Shang and the Zhou dynasties, to around 256 B.C. The earliest Chinese bronzes
were made by piece-mould casting. Bronze played an important role in the culture. Bronze sculptures have been found in the burial tombs of Chinese emperors.


Ancient Greece

The technique of bronze casting was brought to Greece from Egypt. The Greek mainland was prosperous during the Mycenaean age,
from 1600 to 1100 B.C., and both luxury and everyday objects were sometimes made from bronze.

Hammered sculpture was made until ca. 500 B.C. when lost-wax casting began to be used more. Sculptures often were inlaid with glass,
silver or copper to form lifelike details. By the 6th century B.C., there were foundries to cast large hollow bronzes. Parts of the statues were
joined together with molten lead. Most statues were melted down for reuse. Some statues from the period survived by being lost in
shipwrecks and have recently been discovered.

Statues are thought to have been produced in series, not as uniquely produced pieces by the artist. Ready-made limbs might even have
been added to torsos that were cast separately. The lost-wax process allowed for serial production of bronzes from the same original.

An Etruscan earthenware vase called the Foundry Cup has a painting on it that shows a production line for bronzes. On one side, a
worker is assembling the parts of a graceful nude sculpture, while the other side depicts an archaic, stiff figure of a warrior made in a
style once thought to be older. This Cup suggests that both styles were used at the same time.


Ancient Rome

Many bronze statues in other lands were removed and sent to Rome where they were melted down and reused for weapons or
Roman sculpture. In the 1st century A.D., Pliny the Elder wrote about Rome's reuse of copper in foundries at Brindisi.

In 1992 bronze parts of sculpture were discovered in the Mediterranean Sea off Brindisi, at an ancient shipwreck. The sculptures were
found to have come from the Roman Empire's eastern Mediterranean territories, and were dated from the 4th century B.C. to 300 A.D.
This is strong evidence that the Romans practised bronze recycling.


Thailand 1500 B.C. to 700 A.D.

There is evidence of bronzework in Thailand dating back to 1500 B.C., that was cast by the hollow lost-wax method. By 700 A.D. this
technique was used to form images of Buddha. The lost-wax method continues to be used in Thailand today.


West Africa 900 A.D.

Evidence has been found in what is now Nigeria, of bronze castings that date to 900 A.D.

The Igbo-Ukwu people may have been some of the earliest in West Africa to produce bronze sculptures with the lost-wax technique.
There are decorated and cast vessels, crowns, breastplates and swords. Many pieces were produced with several castings and by
joining separate sections of a large work. Many sculptures are made of only a thin wall of bronze, held in place during casting around a
clay core. If the clay could be reached after casting, it was broken and removed.


Renaissance Italy 1400 to 1600

In the 1400s bronze began to be used for sculpture. Florence was the centre of bronze artwork, and home to two key artists, Lorenzo
Ghiberti as well as Donatello. He lived from 1386 to 1466 and is considered to be the greatest sculptor of the early Renaissance.

Donatello created works for churches among others, and influenced other sculptors, including Michelangelo, into the 16th century. During
the second half of the 1400s, small bronze and brass statues became popular. These were created by the lost-wax technique, although
early ones were created by solid cast or by the direct lost-wax method.


Americas from pre-Columbian times to the present

Hammered copper sculpture has been produced in central Mexico going back to the Purepecha Indians of pre-Columbian times. In the mid
1500s the Spanish founded Santa Clara del Cobre as a centre for copper smelting. Copper sculpture continues there to the present day. In
1968 the town was asked to create the Olympic torch for the Mexico Olympic Games.

Pure copper is used, but copper is no longer mined locally. Today only scrap copper is reused. The hammered technique is used. First, the
copper is heated in a bonfire until it can be shaped by hammer, first into the shape of a bucket, then into anything desired. Designs can be
put onto the piece with special hammers. A rich chestnut-coloured patina results from the flame, soot and ash.


France 1877 - 1921

Auguste Rodin, born 1840, was influenced by Michelangelo. The bronze work called The Age of Bronze was the first full-size nude figure
that Rodin exhibited under his name, in 1877. The French Ministry of Fine Arts bought The Age of Bronze for the Luxembourg Gardens in
Paris. Rodin's Adam, also called The Creation of Man, was directly inspired by Michelangelo's work.

In 1880 the French government commissioned Rodin to produce an enormous carved set of doors for a planned museum. The 21-foot-tall
doors were never able to be cast in bronze during Rodin's life. The clay models for sections of the doors crumbled before Rodin could
complete the composition. Many of these figures were cast in bronze as individual sculptures. In 1916 Rodin gave his collection to France,
asking that a museum be created for it. The result was the Musée Rodin, which is in Paris.

Edgar Degas, born 1834, was a sculptor who did not show his work publicly. At his death in 1917, more than 150 sculptures were
discovered in his studio. None had been cast. By 1918 his heirs authorized bronze casts to be made of 72 of the small figures. Sculptor
Paul-Albert Bartholomé was asked to prepare the works for casting by the Paris foundry of A.-A. Hébrard et Cie. Twenty-two casts
were made of each figure, which included one for Degas' family and one for the foundry.

Moulds were first carefully made of Degas' fragile originals. The moulds were then used to cast master models in bronze, which were
used to make the moulds for the wax models that were used in the lost-wax casting. The first series of these bronzes was exhibited in
Paris in 1921. Now, all but two of these sculptures are in the Metropolitan Museum in New York. The original Degas sculptures and the
master models for casting were kept and put on the market in the U.S. in 1955 and in the early 1970s. Most of these works are now in
Washington and California museums.


United States

Before the mid 1800s, Americans did not have the technology to cast bronze. By the late 1840s, Henry Kirke Brown had built a foundry to
cast his own bronze sculptures. He worked with Ames Manufacturing Company, a maker of cannons and swords, which became the first
foundry in the U.S. to become skilled at bronze casting.

By 1850 foundries began to be established for casting bronze, which was considered stronger and more practical than marble. During the
late 1800s bronze was used more often than marble. After the Civil War, bronze casting spread to cities on the east coast. Sculptors were
able to choose the foundries best able to produce the desired results. Some of the most impressive American bronzes are the result of team
work between the artist and foundry workers who collaborated on decisions about scale, form, texture, surface and colour. Frederic
Remington's work with the New York foundries Henry Bonnard and Roman Bronze Works is some of the best American bronzes ever made.

In 1867 the American sculptor Augustus Saint-Gaudens moved to Paris to study art, and in 1870 he began working in Rome. His greatest inspiration came from the 15th-century artists Pisanello, Ghiberti, Verrocchio and Donatello. In 1877 he created an over-lifesize bronze
statue for a park in New York. The success of this monument led to commissions for 20 other public monuments. In 1891 Saint-Gaudens
sculpted a female nude Diana in gilt sheet copper to be placed on top of Madison Square Garden. This was 18 feet (5.5-m) tall and was
too big for the roof tower, so a 13-foot (3.9-m) statue was created instead.

In 1892 Saint-Gaudens began work on his final major public statue, a gilded bronze of General Sherman on a horse, being led by a winged
female figure of victory. By 1900 he was considered the foremost American sculptor of his time. In 1905 he was asked to redesign the
country's $10 and $20 gold coins, establishing himself as a master of both large and small sculpture.

Before 1900, American bronzes were made by the sand cast method. By 1900, Roman Bronze Works became the first U.S. foundry to
specialize in the lost-wax method. Around 1900, bronze statuettes became widely popular. Some, like Remington's Bronco Buster, were
cast in large editions to satisfy the market. Sculptors began experimenting with surface finishes and patinas, which ranged from black
and brown to innovative greens, blues, golds and yellows. W.W.I caused a stop in developments in art bronze casting. The great age of
American bronze sculpture was between the Civil War and W.W.I.