Coloured Glass
VASE IN BLUE GLASS
By Wilhclm Wagenfeld, Oberlausitzcr Glaswcrke,
Germany, 1940. Ht. 560 mm (22 in.)
Blue glass has retained its popularity to
modern times. An example of this is the
steel blue vase designed by Wilhelm
Wagenfeld of Germany. Born in iqoo and
trained at the Bauhaus and the Kunst-
gewerbeschule in Stuttgart, he is one of the
pioneers of modern ideas in factory-
produced glass. His simple, elegant glass
forms bear witness to the profound feeling
he has for the special properties of glass as
an artist’s material. Wagenfeld taught
metalwork at the Weimar College of
Architecture, as well as designing for the
glass, metal, jewellery and porcelain
industries. Later he became a professor at
the Academy of Fine Art in Berlin, and
finally took over the artistic direction of the
then Vereinigte I.ausitzer Glaswerkc. He
was thus able to put into practice his ideas
on glass-making, and he influenced the
products of a whole industry, so that not
only the art pieces, but also the mass-
produced articles exhibit aesthetic as well
as technical quality.
Alabastron with opaque red body, with light
blue and yellow opaque traii.s
I Icllcnic, 6th 5th century b.C.
Hi. 100 mm (3*95 in.)
Red Glass: Ancient red glass was generally
made by adding copper (cuprous oxide) to
the mix in a reducing (non-oxidising)
atmosphere in the furnace, which resulted
in a brilliant red opaque glass. That the
ancient glass-makers were quite aware of
the difference between oxidising and
reducing atmospheres is clear from the
Mesopotamian recipes, where they are
directed to use either a smoky fire in the
furnace (non-oxidising) or a smokeless fire
(oxidising). It is worth noting that the
tablets found at Nineveh, which give
detailed directions for the preparation of
coloured glass, and which are dated to the
7th century B.C., could on the basis of
literary style be copies of texts some
centuries earlier. A fine opaque red glass
from copper was made in Egypt certainly
from the XVIIIth dynasty. The process
was as follows: copper—containing glass
would be melted in a reducing atmosphere,
causing particles of red cuprous oxide
and/or copper itself to be precipitated in
suspension throughout the glass.
BOTTI.E IN DEEP RED GLASS WITH OPAQUE Will I
HANDLES
The addition of lead to the mix would
the process just described, because 1
increased the solubility of copper at
temperatures and caused this solubilit
decrease rapidly as the temperature
lowered, thereby enabling more cupr
oxide to be precipitated. Most of the
early glasses that contain lead have
opaque red colour. The earliest ex
recorded of a glass containing lead oxid
a major constituent is a sealing-wax
glass found at Nimrud dating from
tween the 8th century and the 6th
B.C. The Roman author Pliny mentioned
an opaque red glass called haematimim
and seemed to imply it was of
(Italian) manufacture. One analysis of)
opaque red glass from a Roman Italian
proved it to be a soda-lime-lcad g
coloured with a high proportion of cupr jus
oxide. Glasses coloured red with cuprous
oxide were apparently not made in Ron lan

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