Antique Coloured Glass
Coloured glass
Coloured glass is made by adding metallic oxides to the glass batch. This technique was widely practised in ancient Egypt and Rome, where brightly coloured glass was often favoured over clear glass. In the 15th century opaque white glass, slightly translucent glass, and glass in imitation of hardstones were produced in Venice; in Bohemia glass in bold colours of blue and
ruby-red was widely produced before 1800. In the 19th century, with advanced technical and mass production methods production was much more widespread with notable firm operating not only in Italy and Bohemia but also in Britain France, and the USA. Experimention with new staining any overlay techniques produced a wide array of coloured designs.
EARLY GLASS
The Egyptians experimented with coloured glass, exploiting their extensive trade routes to acquire the necessary materials. Ancient Egyptian glass comes in a myriad of bright, pure colours. One of the most common was bright turquoise blue, coloured by adding copper oxide to the batch. Antimony and tin oxide, imported from Assyria, were used to colour glass an opaque white, while pure opaque yellow was trailed over dark blue core-formed objects, with white or pale blue, and
combed into festoons or feathery patterns and zigzags. Fine alabastra (bottles or flasks) known as “gold-band” incorporate stripes of real gold.
The Romans continued to experiment with coloured glass, producing most famously dark blue glass overlaid with opaque white and cut with cameo decoration. Mosaic glass was made from brilliantly coloured canes of glass cut into tiny slices and fused together in a mould. Most coloured glass was blue, although purple and amber pieces are also found. Much excavated Roman glass will have an iridescent surface; this is the result of a chemical reaction with the metal oxides in the earth after the glass was buried. Roman wares include bowls, bottles, flasks, and cups.
VENETIAN GLASS
From the mid-15th century the sophisticated know-how of Venetian glassmakers gave rise to many different types and effective combinations of coloured glass. In the late 15th century a “milky” opaque-white glass made by adding tin oxide to the batch was developed. This glass (known as lattimo in Italy) resembled porcelain, and it became particularly popular in the late 17th and early 18th centuries, when imported Chinese porcelain was in vogue. From the late 15th century a fine marbled glass known as “chalcedony” ” or “agate” glass was created by mixing together coloured opaque metals to resemble hardstones. Opaline glass, which was slightly translucent and less dense than opaque-white glass, was probably first made in Venice in the 17th century by the addition of oxides and the ashes of calcified
bones to the batch; when held to the light it can be distinguished from opaque-white glass by a red or yellow tint, which is known as the “fire’
BOHEMIAN GLASS
In the 16th century a distinctive dark-blue glass was produced in Bohemia by the addition of cobalt oxide. The clear vivid body colour was a perfect canvas for the brightly coloured naive enamelling popular at that time. At the end of the 17th century a deep pink glass was invented by by Johann Kunckel (c.1630-1703), a chemist and director at the Potsdam Glasshouse (est. 1679). The colour was produced by adding gold chloride to the batch. This “gold-ruby” glass (known as “Kunckel red” or, in German, Rubinglas or Goldrubinglas) was also produced in Nuremberg and other glasshouses in southern Germany. Gold-ruby glass was decorated with engraving, cutting, or gilding, and was considered a luxury product.
• MAIN AREAS OF PRODUCTION ancient coloured glass was made in Egypt and Rome; it was produced from c.1450 in Venice and from the 16th century in Bohemia
• TYPES blue glass; porcelain-like “milk” glass; coloured glass in imitation of hardstones; opaline glass; gold-
ruby glass
• FORMS densely coloured pieces may appear heavy bodied
• COLOURS ancient glass: many pieces have dark blue bodies sometimes with yellow and white decoration
• COLLECTING ancient Egyptian glass is very rare and valuable; generally colour will not play an important part in its value; gold-ruby glass is rare and valuable
Bohemia
The 19th century was an age of experimentation in glass technology. Glassmakers, some of whom were also skilled chemists, developed new colours, new ways of applying colour, and innovative techniques to produce glass
The most celebrated types of Bohemian glass from this period are “Lithyalin”, “Hyalith”, stained, and flashed glass.
LITHYALIN AND HYALITH GLASS
Count Georg Franz August Langueval von Buquoy 1811-1851), the owner of a number of glasshouses in southern Bohemia, produced an opaque black glass c.1817, which was inspired by the black basalt wares produced from the end of the 18th century at the Wedgwood factory (est. 1769) in England. In 1819 lie produced another dense opaque glass, known as -Hyalith”, usually in sealing-wax
red or jet-black. Hyalith was usually decorated with gilding.
Von Buquoy’s experiments may have inspired Friedrich Egermann (1777-1864), who in 1829 at his factory in Haida, northern Bohemia, patented “Lithyalin” glass, a polished opaque glass that resembled hardstones, which he continued to produce until 1840. The surface of the glass was brushed with metal oxides to resemble veining and marbling. Strong colours are typical, especially red; more unusual are dark-green, blue, and purple. Wares were usually cut and polished and occasionally gilded or enamelled. Lithyalin glass was used mainly
~, vases,
for purely decorative items, notabl
and scent bottles. Lithyalin glass was also produced at the Harrach Glassworks (est. 1`14) in Neuwelt (now Novy Svet in the Czech Republic), and by Hautin & Co. in France. Although these copies are difficult to distinguish from pieces by Egermann, they are usually slightly lighter in colour.
STAINED, FLASHED, AND OVERLAY GLASS Egermann also invented an effective and inexpensive method of colouring glass with a
thin stain of colour, which was called flashing. This involved painting a clear object with a stain and firing it at a low temperature to fix the colour. This gave a solid, even, pale colour. Egermann is particularly noted for his yellow coloured stain, developed in 1818 using silver chloride, and his ruby-red stain, perfected in 1832, using gold
chloride and copper oxide. Wares were often cut through to the thin colour to reveal the clear glass beneath.
In casing – a technique reinvented by Egermann –the glass vessel is covered in a differently coloured glass and then fired; as the glass cools, the two layers fuse together. Some pieces were “double-cased”, i.e. dipped into two differently coloured batches of glass to give a multicoloured effect. The flashing technique is sometimes confused with casing as the terms were used interchangeably by some glassworks; however, in casing the layers of glass are much thicker. If there is a sharp line between the two colours, this suggests flashing, whereas shading or thinning between two colours suggests overlay. Flashing and staining are characteristic of 19th-century Bohemian glassmakers as they are inexpensive methods of colouring glass and thus well suited to the mass-produced wares made during the 19th century.
OTHER COLOURED GLASS
During the 1820s and 1830s a series of
industrial exhibitions held in Prague gave rise to the development of other types of coloured glass, including violet, pink, green, and blue. Further experimentation with colour in the early
I 9th century sparked the discovery in Bohemia of other ways to colour glass. Of particular note is the work of Josef Riedel (active 1830-48), who in the 1830s used uranium to produce a vivid fluorescent greenish-yellow (Annagriin) and yellowish-green (Annagelb) glass, both named after his wife Anna. However, this glass was mildly radioactive, and the process was later abandoned.
Lithyalin and Hyalith glass
• CONDITION ceramic restoration techniques are often used, so repairs can be difficult to spot
• COLLECTING display vessels such as vases and bowls arc most common; display cups and saucers and pieces with gilt oriental and chinoiserie decoration are rarer; lithyalin overlaid on dark-green hyalith is valuable
Flashed, stained, and overlay glass
• CONDITION check pieces carefully, as damage is often hard to detect on coloured glass; good condition is vital
• COLLECTING the condition and depth of the colour determine the value; beware when collecting blue stained glass as it fades easily and can lose value
Other Bohemian coloured glassTYPES
• vivid green Annagriin and Annagelb glass
Britain, France, and the United States after 1800
Coloured glass was widely produced during the 19th century in Britain, France, and the USA. In Britain two important events gave a new impetus to the manufacture of coloured glass in the middle of the century. The first was the removal of excise tax on glass in 1845, which encouraged makers to experiment with new techniques and styles, among them coloured glass. The second was the Great Exhibition held in London in 1851 at which glassmakers from Europe and the USA were keen to show their new skills and techniques. In France glassmakers at all the major factories manufactured coloured glass in a range of styles and forms, and in the USA firms experimented widely with colour, producing an extensive range of designs, most characteristically in delicate pastel shades with subtle
BRITAIN
All blue, green, and amethyst glass produced in Britain from the end of the 18th to the middle of the 19th century is generically described as “Bristol” glass. The most characteristic colour is a brilliant royal blue, produced by adding cobalt oxide to the batch; such glass is frequently embellished with cold gilding. Drinking glasses were generally green, ranging from grass green to a turquoise green. Amethyst glasses are rare, but when found the colour is true and clear, with no sign of red, unlike the plum tone found on later Victorian glass.
In the mid-19th century the influence of coloured glass manufactured by well-established glass companies in Bohemia became increasingly visible in the products of British factories. Not only did important Bohemian factories such as the Harrach Glassworks (est. 1714) in Neuwelt (now Novy Svet in the Czech Republic) exhibit quantities of coloured glass at the Great Exhibition, but Bohemian glassworkers were also employed by British factories where, freed from the constraint of having to produce wares in traditional styles, they were able to manufacture very exciting wares in an outstanding range of new colours.
In the late I 870s a type of
type
opalescent glass, known as
“Vaseline” glass due to its greasy,
vaseline-like appearance, was developed
in Britain and designed to resemble 15th-
and 16th-century Venetian glass. The opalescent colour was produced by using tiny amounts of uranium together with other metal oxides to create shades of yellow, green, blue, and, more rarely, red. Stevens & Williams Ltd (est. 1847), of Brierley Hill, near Stourbridge, was one of the leading innovators in the field of patent colours and colour combinations in the late 19th and early 20th centuries. The company’s rare double-cased “Rockingham” ware is particularly sought after, as are the Bohemian-style
pieces with alternating panels of engraved colour-flashed and clear glass produced by WIT.,
B. & J. Richardson (est. c.1836), also near Stourbridge. Amber was the most commonly used colour for the vases, decanters, and claret jugs in this style, although some pieces were also produced in purple, green, and red.
Gold and uranium oxides combined with sodium nitrate were used to manufacture the “Queen’s Burmese” range of glass by Thomas Webb & Sons (est. 1837), near Stourbridge, patented in 1886. Queen’s Burmese was inspired by the “Burmese” glassware patented in 1885
by the Mount Washington Glass Co. (est. 1837), in South Boston, Massachusetts, and favoured by Queen Victoria who ordered a set – hence the name. It had a body colour that shaded from a pale lemon-yellow (sometimes light green) at the bottom through to salmon-pink at the top. Some pieces feature enamelled and gilded designs. Although Queen’s Burmese ware was made by other British companies – including WIL, B. & J. Richardson –pieces by Webb are the most desirable. Typical wares include vases, posy bowls, and lampshades. Another type of glass introduced by Webb was “Peach” glass, a type of cased glass that shaded from pink through to a deep red.
A Tazza
The tazza is a distinctive Venetian form of serving dish. The revival of 15th- and 16th-century Venetian glass forms and styles of decoration was started in Venice during the mid-19th century and gradually spread throughout Europe. In Britain the Revival was supported by William Morris, who disapproved of the heavily cut glass prevalent at the time. One of the leading British manufacturers of Venetian Revival glass was James Powell & Sons (est. 1834), which produced “Vaseline” glass wares similar to the example shown above, and in delicately tinted glass from the 1870s.
FRANCE
In France, the Baccarat Glassworks (est. 1764 as the Sainte-Anne Glassworks) in Baccarat, near Luneville, Lorraine, produced glass c.1880 in a distinctive, delicate shade of pink known as “tinted-rose”.Many
wares feature acid-etched Classical decoration. Another fashionable trend was the production of coloured opaline glass, a semi-opaque white glass, opacified by the addition of the ash of calcined bones and coloured with metallic oxides. The Venetians had been the first to introduce this translucent glass, which was later made in Bohemia and Britain, but the French opaline glass first produced c.1823 at Baccarat was more translucent. The finest French opaline was made at Baccarat, at the Saint-Louis Glassworks est. 1767) near Bitche, in the Munzthal, Lorraine, and at the Choisy-le-Roi Glassworks (est. 1821) in Paris. Wares were made in delicate pastel shades such
as turquoise, pink, and pale green, and include pairs Of vases with enamelled decoration, and vases, jugs, and dishes of inventive forms, often with coloured cane rims. Saint-Louis Glassworks made many pieces IT soft pink or blue, with latticinio decoration and glass cane rims.
THE UNITED STATES
Throughout the 19th century American glass manufacturers launched and developed a range of innovative coloured glass. One of the most popular and now widely collected colours is the transparent “Cranberry” glass, which has a distinctive raspberry pink tint, first produced in the glassmaking region of Stourbridge in England. Huge quantities of useful and ornamental wares were made, most notably at the Boston & Sandwich Glass Co. (1826-88) in Sandwich, Massachusetts.
However, it was only during the 1880s, when there was a move away from cut and pressed glass by the leading glass manufacturers, that they began to experiment in earnest with a more sophisticated range of coloured art glass. One of the leading companies at this time was the Mount Washington
Glass Co., which launched the widely copied and enormously popular “Burmese” glass in 1885. Most Burmese glass has a satin finish, although some has a glossy surface, and is characterized by subtle gradations of shading from a light lemon at the bottom of the piece to a delicate pink at the top. In 1883 the firm of Hobbs, Brockunier & Co. (est. 1863) in Wheeling, West Virginia, developed “Peachblow” glass and incorporated it into its range of coloured wares. This cased glass is a warm buttery yellow at the base shading through to a purplish-red at the top and is lined in a white opal glass. Peachblow was made at other companies, including the New England Glass Co. (1818-90), originally in East Cambridge, Massachusetts, which called it “Wild Rose”. New England was also notable for its “Amberina” range of glass, which it produced as “Pressed Amberina”. Both Wild Rose and Pressed Amberina were developed by Joseph Locke (1846-1936), an English glassworker, who emigrated to the USA in 1882. Patented in 1883, Amberina glass contained small amounts of gold, and graduated from pale amber at the base through to a rich fuschia at the top. It was made until 1900. Hobbs, Brockunier & Co. also made Pressed Amberina under licence from the New England Glass Co.
France
• MAJOR FACTORIES Baccarat, Saint-Louis, Choisy-le-Roi
• TYPES pastel-coloured opaline glass and wares with decoration are most notable
• COLLECTING wares by Baccarat are sought after
Marks
Saint-Louis: this mark was used from 1870 to the present day; some pieces marked “Argental” or Munzthal the German for Argental, often with a tiny cross of Lorraine
The United States
• COLLECTING Cranberry glass: very popular with
collectors; later Cranberry tends to have a less warm hue and a bluey tinge when held to the light
Marks
Mount Washington Glass Co.: mark used on Burmese ware from the 1880s
New England Glass Co.: Amberina ware; mark used from 1880s
Britain
• TYPES Bristol glass, overlay glass, Vaseline glass, decorated opaque and opaline glass
• BEWARE there are many early 20th-century copies of Bristol glass: beware of glasses that are larger than usual (more than c. I Ocin/4in high) and thin glass
Marks
Thomas Webb & Son