The alchemy behind Victorian coloured glassware
Time for a significant splash of colour in
our next article, and a look at some pieces from the 19th century, which saw
the creation of some amazing artefacts using increasingly complex production
techniques and innovative processes to impart coloured finishes.
The use of colour in Victorian glassware
became far more extravagant and involved than that of any earlier period to
date. Throughout Georgian and Regency times coloured pieces tended to consist
of one uniform hue in their entirety, or with individually-tinted pieces being
combined to give the appearance of multi-coloured items. The inclusion of
coloured rods in the make-up of opaque or air-twist stems produced some
particularly striking pieces, but it was to pale in to insignificance with the
results of subsequent advancements. The latter decades of the 19th century saw
a proliferation of techniques which resulted in a variety of innovative and highly
decorative effects, from the use of subtle graduations in tone to vibrant
pigmentation and pieces of overtly ostentatious tincture.
The processes behind the creation of some
particularly popular types of coloured glass exhibited the splendidly injudicious
mindset of Victorian Britain in full innovative spate; the blues, yellows and
opalescent white edging of Davidsons’ patented Pearlescent range, for instance,
required the addition of arsenic and uranium during manufacture – not the sort
of thing that you imagine would have left the craftsmen of the time entirely
unscathed. However, not all such finishes were quite so inherently dangerous to
achieve, with marbled or malachite glass being made with the inclusion of
common or garden mining slag. It is of interest to note that the primrose
yellow Pearlescent pieces tinted with uranium dioxide or pitchblende (known as
Vaseline glass) glow fluorescent green under ultra violet light – an
irrefutable test of authenticity.
Of a similarly rather imprudent nature was
the pursuit of effective silvering for glass for decorative purposes rather
than use for mirroring. The long-standing quest for the refinement of this
mirrored appearance had already employed tin and bismuth, and to a lesser
extent mercury, and it was the latter, potentially more lethal of these which
naturally proved to be the preferred Victorian constituent. It was not,
however, added to molten glass in powdered form as was normally the case with
ingredients which were intended to impart a particular hue. Rather molten
mercury – or less often silver nitrate – was introduced to fill a paper-thin
cavity in double-walled vessels, with the aperture in which it was encapsulated
having to be plugged with a disc-seal – invariably carrying the name of the 1849
patent holders for the process, Hale Thomson and Edward Varnish. For additional
embellishment the outer of the two skins could be made from “standard”
wholly-coloured glass – known as flashing – with this external layer then being
cut or deeply etched to make the silver underneath visible and part of any
design.
Of course, it the production of coloured
glassware was not a peculiarly British preserve, and the glasshouses of the
continent also excelled themselves with the production of some truly stunning pieces.
Some examples of Bohemian glass from this period almost defy description, with
their use of deep colours, detailed engraving, etching and flashing.
While we are at it – and as it is often
mentioned in our pages – it’s worth defining what area actually constituted
Bohemia during the period in which most of the glass we display was produced.
It was for the most part the majority of the Western half of the modern day
Czech Republic, including the ancient Kingdom of Bohemia itself, sundry
Silesian regions, Moravia and the Eastern extremities of Carpathian Ruthenia.
Glass production was centered on the towns of Jablonec, Skalice, Poděbrady and
Karlovy Vary.
Although the use of coloured rods had been
used to construct twist stems during the 1700’s, the refinement of the
techniques involved in applying the tinting media to the glass melt, the way in
which twists were processed and in which finished pieces were assembled meant
that later pieces really did look quite extraordinary – I’d suggest that you
visit our site and take a look at the Josephinenhutte opaque colour twist
glasses (from Piechowice on the northern fringes of Bohemia, made right at the
end of the 1890’s) for some particularly stunning examples – the link to the
relevant page is below.
Somewhat nearer to the other end of the
spectrum of luxuriance – and by way of whole-colour pieces rather than compound
glassware – we find what was termed milk glass, produced in Victorian times as
a cheap alternative to porcelain and a derivative of 16th century Venetian opal
glass technology. This saw opaquing elements added to the melt during
production – originally ash or bone which produced the white colouration that
gave the product its name, but also tin, arsenic and antimony as additives for
the optional blue, black and occasionally green pigmentation of this
utilitarian but still fetching and very collectable denomination. Such was the
demand for coloured glass during the latter part of the 19th century that this
age-old process was revived to cater for the demand. This saw – most notably –
Thomas Webb’s commercial application of the processes required to produce cameo
glass, refining knowledge which had existed since Roman times. In simple terms,
vessels would be produced using opaque and coloured layers of glass, then a
design marked out on to the outermost (opaque) surface using acid-resistant
material, with the un-masked portion of the same layer then dissolved away to
leave an image slightly in relief of its now coloured background.
Of a similar nature was the process of
“cut to clear” glassmaking. Again, two layers of glass were utilised, but in
this instance a coloured outer flashing layer was moulded over a clear glass
inner blank. The outer face was then cut, rather than etched, to reveal the
clear glass underneath. The lack of an opaque layer in this procedure produced
pieces which were far more readily interactive with light, and – coupled with
the myriad reflective facets of the cutting – made for some particularly
striking pieces. Essentially the same as the process for producing what were
termed overlayed vessels, the complexity could be further augmented by using a
further, third coloured glass layer.
When one remembers that more standard
methods of decoration such as gilding and enameling were also available to
Victorian glassmakers it can be of no surprise that the period saw a huge
volume of coloured material produced. Cranberry (or ruby) glass – beautiful,
pale red, fine lead crystal tinted with compounds of gold – was in its lustrous
heyday; satin glass – chemically treated opaque pieces similar to milk glass
but coloured more richly – was also profligate (and required the acutely
dangerous fumes of hydrofluoric acid during production, so fulfilling a
seemingly vital criteria of the day !). Fortunately, quality – for once – is
not greatly compromised by quantity, and Victorian coloured glassware therefore
provides a rich and varied department for collectors to explore and enjoy, and
with a bit of judicious searching it is possible to track down some very
striking pieces as surprisingly realistic prices (most of which, obviously, are
on our own website).
As ever, click the following links to
visit our website where you can see many pictures of all the items mentioned
above.
site search results – Victorian coloured glass
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