Sep
15
Antique Glass Designs
September 15, 2009 |
NECKLACE WITH FACET-CUT BEADS
Persia, 1000-800 B.C.
Grinding and Cutting from a raw Block of
Glass is a technique which dates from the
earliest times of glass-making. It is known
to have been used on vessels from at latest
the 8th century B.C., and was one of the
main methods employed for finishing off
the finest, usually colourless, glassware in
Assyrian, Achaemenian and Hellenistic
times. In ‘cold cutting’, as it is more
simply known, objects and vessels were
fashioned from a block of glass by the
use of a rotating wheel, with a harder
material like flint or quartz (probably in
powdered form) applied to its edge. Glass
has a hardness of about 6, and can readily
be ground or cut by these harder materials.
Occasionally, the technique was used to
fashion an object entirely from a piece of
glass, as is most likely the case with the
larger faceted beads in the necklace
illustrated. More often, an object would
first be roughly cast in a mould, and the
finer details would then be added by this
grinding technique.
Alabasiron engraved with the name of .sargon ii
Nimrud, Assyria, 722-705 b.C.
Hi. 80 mm (315 in.)
One of the most remarkable examples of
the grinding technique is the alabaslron in
the British Museum which bears the name
of King Sargon II (722-705 B.C.), found
at Nimrud in 1850. It was apparently
ground from a raw block of glass, for it
shows very clearly on its interior the spiral
grooving left by the grinding tool, thought
to have been a flint scraper. What estab-
lishes its 8th-century origin is a horizontal
line of engraving on front and back
between the lugs, comprising a lion, facing
right, and a cuneiform inscription which
when translated reads ‘Palace of Sargon,
King of Assyria’. It is in clear green glass,
with a thick white-to-brown enamel-like
weathering in parts on the outside.
FOOTED CUP with wing HANDlES
Gmom, Italy, late 3rd century b.C.
Ht. 111 mm (4-35 in.)
ant
Cold cutting ignored the ductility
manipulative qualities of the glass in
favour of copying shapes used by othel,
craftsmen such as metalsmiths and pottery,
makers. In the above example, theltwd
projecting wing handles resemble thos<
common in the silverwork of antiquity, anc
impose a false stiffness on the glass shape.)
The glass has in a sense been misused by
the cold cutting method. It must have been
a most laborious technique, surely hafdei
than the core technique when used fori the
production of small vessels. The cup was
apparently cast in a two-piece mould!
(probably as a thick blank with solid
handles) and finished by cutting and
grinding. The way the handles have been
cut out of solid glass, reminiscent of the
work of the carver in hard-stone, shows all
too clearly the influence of the gem-cu tter
on glass-making techniques in anc ent
times.
Techniques before Blowing
Casting and Pressing Glass into Moulds was
a technique borrowed from workers in
pottery and faience. It was used not only
for vessels, but also for solid objects such
as ornaments, inlays and statuettes. Objects
which would only be viewed from one side
could be pressed in open moulds with the
pattern on the inside. The glass could have
been in either molten or powdered form
when put into the mould. It would be fired
in a kiln, then cooled slowly, to take out
any strains in the glass. In the figurine of
Astarte there is evidence that the back was
flattened by pressure—presumably the
glass-maker pressing the glass firmly into
the mould. When the glass had finally
cooled, it would be removed from the
mould and used as desired. The glass used
for the figurine of Astarte was originally a
translucent greenish-colourless type, and
now appears opaque white because of
weathering.
Objects which were modelled in the round
were cast in two-piece moulds. The
figurine of the Egyptian God Bes has been
made in this manner, with details lightly
incised afterwards with a pointed instru-
ment. It is in blue-coloured glass, seeking
presumably to imitate lapis lazuli, which
was very popular with the people of the
period. Most if not all of the early glass-
making moulds which have been found are
made of clay, and it is probable that the
designs on them were impressed from a
wooden (or similar) original. Simple hem-
ispherical bowls were also produced by
casting in a two-piece mould. The cire
perdue process (which will be described
shortly) could have been used, or powdered
glass could have been placed between two
parts of a closed mould and fired in a kiln
to produce the bowls. The mould would
have had to be broken away once the glass
had been slowly cooled (annealed), and the
bowl would then be ground and polished
to smoothness.