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Engraving and Decorating Glass
Methods and Techniques
By Barbara Norman
Dover Publications, Inc.Copyright © 1972 Barbara Norman
All rights reserved.
The Development of Glass
Many people think of glass—if they think about it at all—in very general terms. They are aware that it can be blown in some way, that there are such things as stained glass, cut glass and Venetian glass, that it is sometimes engraved, and that nowadays much of it comes from Czechoslovakia and Sweden. All these generalisations are true, but behind the bare facts lies a long and fascinating history much of which is bound up with decoration of one kind or another since, right from its beginnings, glass was a luxury article and much creative effort was lavished on it. Only relatively recently, with the introduction of mass production, has it been thought of by so many people as a very ordinary, everyday product.
How it all started is not known for certain, but an accidental discovery is accepted as at least likely. A story told by Pliny is generally not now believed, though no better explanation has been forthcoming so far. According to Pliny, some merchants sailing in the Mediterranean camped ashore for the night on the estuary of the river Belus. They made a fire for cooking, and supported their cooking pots on some of the blocks of natron (a form of soda) which they were carrying as cargo. Later, they discovered that the heat of the fire had fused the natron and sand into a substance which was new to them—glass. And ever since those remote times, soda and silica have formed the basis of glass, although as time went by and knowledge and skill increased, other ingredients were added to produce stability and strength, or colour, or clarity. Pliny wrote in the first century AD, but the earliest piece of glass ever found is a bead discovered in Egypt, and which has been dated at about 3000 BC. There is thus a very large gap in time between Pliny's story and the probable first use of glass so the facts may never now be known.
At first, glass was not blown at all. That process came much later. The Egyptians had some very early uses of glass, putting it on pottery as a glaze. Then came glass objects, such as the bead already mentioned and finally glass shapes which could support themselves. These early glass vessels were made by a most ingenious process called core-winding. A central shape or core was made of some material, possibly clay bound with straw. A rod was attached to this core, and threads of molten glass were trailed over the core until it was completely covered, the whole being frequently reheated to keep it in a workable condition. One of the earliest known glass vessels made by this method is a small vase owned by the British Museum, dated at some time between 2050 and 2000 BC. Beautiful and complicated decorations were often applied, including the fixing of handles and the trailing of threads of glass over the main part of the vessel; some sort of comb-like tool was used to make them into patterns of wavy lines. This kind of decoration, although extremely simple, is very attractive: it reminds me irresistibly of the icing on French mille-feuilles pastries—where indeed pretty much the same method is used to get the wavy lines! In due course the glass was cooled, the rod removed and the core scraped out.
The whole method sounds primitive, but vessels of great beauty were made in this way. Enormous care was taken to remove any defects which—inevitably—appeared, and the cooled glass was ground and polished. If the opening in the neck of the vessel was large enough, as much as possible of the inside was smoothed out too. When it is remembered what a difficult substance glass is to work on compared with, for example, clay, these early glass vessels are amazingly well made. One can only marvel at the way a molten substance which can never even be touched—let alone molded—by hand is shaped into such graceful objects. Glassmaking gradually took root not only in Egypt, where Alexandria was a great manufacturing centre for many centuries, but in other areas of the Middle East, particularly Syria. Throughout the following centuries, both Alexandrian and Syrian glassmaking reached very high standards. The two styles developed separately, Syrian glass becoming more ornate than Alexandrian.
The development of glass followed a very leisurely course: not until somewhere around 50 BC, several thousand years after its unknown beginning, a further discovery was made that molten glass could be blown into shapes on the end of a hollow rod. As in the discovery of making glass, the origins of blowing it are unknown. It is most likely to have been an accidental discovery, but however it came about it was a development of tremendous importance and, apart from various refinements introduced down the centuries, the actual technique of blowing glass, and the tools used, have ever since remained basically the same. Today, when nothing seems to last for five minutes without change and upheaval, and where planned obsolescence is part of life, this thousands of years old continuity of glassmaking methods is a most satisfying thought.
Spreading round the Mediterranean area, glassmaking was practised in turn by the Greeks and the Romans. Roman glass denotes glass of that period rather than glass made by the citizens of Rome themselves, as Rome was not an important centre of manufacture. The Romans appear to have known just about everything as far as glass is concerned except how to make pure sparkling crystal: the world had to wait many centuries for that. The discovery of blowing glass quickly resulted in a great freedom for craftsmen, and Roman glassmakers developed all kinds of techniques. They knew how to engrave it, both in the manner of engravers of precious stones, and in the cameo technique, and also used some kind of sharp tool to produce what was to be the forerunner of diamond point engraving. They could enamel it, gild it, and even use engraved gold sandwiched between two layers of glass—a means of decoration successfully used again in Germany and Bohemia, long after in the eighteenth century. Their glass was often made in a variety of colours, some of which were due to impurities which at that time it was beyond anyone's knowledge to remove. This was particularly true of the greens which began to predominate. As well as making glass by the blowing method, the Romans continued to use molds for some kind of work, particularly when making plaques with any kind of molded design upon them.
The Romans also did some very beautiful work by means of fused glass mosaics. This is just another example of their skill because today, nearly 2,000 years later, people are again doing much the same kind of work with every modern aid, including small electric kilns. Roman fused glass mosaics were made by arranging pieces of different coloured glass in haphazard patterns and fusing them in a furnace. Plaques made by this method were used as jewellery or were inlaid in furniture. Mosaic patterned glass bowls were also made by reheating pieces of coloured glass in a mold. These were known as murrhine bowls.
Roman glass was usually useful, generally decorative, and always extremely elegant. Much of it now has an attractive iridescence as a result of the physical conditions in which it has remained through many centuries; if it has spent hundreds of years buried in dampness it often has an attractive pearly gleam. Many hundreds of years later, towards the end of the nineteenth century, an American, Tiffany, made extensive research into Roman methods of manufacture in an effort to reproduce the iridescence of so much Roman glass. He succeeded in producing what became known as Favrile glass.
The 400 years approximately of the Roman Empire provided the most civilised, well governed and settled conditions the Western world had ever known, and during that time the art of making glass spread to all parts of her vast territory. Glassmakers were often wanderers by temperament, especially the Syrians and, as a result of this, glasshouses were set up further and further afield, spreading gradually northwards over Europe. Apart from an individual's personal desire for change, there was often a real need to move in order to ensure a supply of raw materials. Glasshouses used a vast amount of wood for fuel, as well as quantities of sand: as an illustration of the amount of wood used, glassmakers in England in 1615 were forbidden to use it for fuel because they had made such inroads into the forests. The centres of glassmaking changed constantly over the centuries. In the West, the Roman Empire was already in decay by the beginning of the sixth century and in the resulting chaos all artistic endeavour suffered greatly. But eastwards, in Byzantium and the Near East, this was a time of expansion.
VENETIAN AND GERMAN GLASS
In Western Europe the Dark Ages closed in, and what remained of glassmaking had to be adapted to changed conditions and to fight for survival. Glasshouses, however, appeared towards the north in an area bounded by the Seine and Rhine, and a distinctive kind of Forest glass, called Waldglas, was developed from local ingredients, the alkali content of the glass being obtained from wood ash from the abundant forests. This resulted in a natural colouring of varying pale greens and ambers. The elaborate and beautiful decorations of the Roman world disappeared and there was no more painting, gilding or cutting. However, a modest kind of trail decoration continued to be used. Unlike the north, Venice did not suffer nearly so much during the Dark Ages. By the time of the Crusades, Venetian glass was already highly developed and the commercially minded Venetians were trading far afield.
Ever since the beginning of glassmaking, craftsmen had been striving to make a clear glass, as nearly as possible like natural rock crystal. This goal had often been set aside in the interest of making glass of varied colours, but basically it was always there. At last, in the fifteenth century, the Venetians produced a clear, delicate glass which they called 'cristallo'. In a thick state this was not entirely clear, having a slight greyness, but if blown very thin the greyness almost disappeared: thus began the very distinctive glass whose delicate appearance has come to be linked in most people's minds with Venice. This fine glass was too thin and brittle for cutting or wheel engraving. A limited amount of diamond point engraving was used on it, but it was not generally very suitable for any kind of surface cutting and, because of its fragile nature, decoration was added at the time of manufacture. This added decoration became more and more elaborate and complicated with a great deal of frothy-looking exterior decoration, and almost any very elaborate glass came to mean 'Venetian glass' to future generations.
The Venetians learned how to manipulate glass as no one had done before. Being near the sea, their alkali came from seaweed ash. Glass made of this could be kept in a workable state over a wide range of temperatures, which is one reason why Venetian glass was fashioned into such elaborate patterns.
The Venetians recognised the value of the industry and grouped all glassmakers on the island of Murano, forbidding them to divulge their methods of work or to leave Venice to work elsewhere. However, a famous glassmaking industry was also developing in Altare, near Genoa, and some Venetians did manage to leave Murano to join the Altare craftsmen. In that way, Venetian methods of glassmaking, and Venetian styles, very gradually spread further and further northwards because the Altare industry was not subject to controls and its craftsmen had complete freedom to move as they wished.
The Venetians loved to decorate. They coloured their glass, combining several colours in one object. They painted it in all kinds of ways, sometimes using enamels on clear glass, sometimes painting landscapes on opaque white glass, as for example the eighteenth-century Venetian scenes after Canaletto. They gilded too. But one of the most beautiful and complicated forms of decoration which they invented was 'latticinio'. This was achieved by putting threads of opaque white glass inside clear glass so that when the glass was blown and fashioned in a particular way, the opaque threads arranged themselves into elaborate, perfectly accurate patterns spiralling round the glass or criss-crossing through it. It is elegant and controlled, rather like some kind of interior engraving.
It always seems to me that the Venetians must have greatly enjoyed their glassmaking because their work radiates confidence and pleasure. They appear to have flung themselves wholeheartedly into an absolute welter of inventive shapes and decorations, and only very occasionally to have overdone it a little. It is difficult to imagine their agonising over their work. It seems far more likely that they tossed it off with cheerful pleasure, loving the colours and patterns. Nowadays we can appreciate the natural colours and comfortable shapes of the northern Waldglas, but to people living at the time the clear, fragile Venetian glass must have seemed highly desirable and very civilised. It was a great luxury, which is hardly surprising when one considers the tremendous difficulty of transporting such fragile objects by the means then available. How much must have been broken as it bumped over the rough unsurfaced roads.
Much admired though Venetian glass was, distinctive styles of material and design were developing in other parts of Europe, for instance the use of glass as a decorative material in stained glass windows. Coloured glass windows were known in Europe by the ninth century, and by the thirteenth century this form of decorative glass had reached its greatest heights. There still remains a great deal to be seen throughout Europe, ranging from a single window in many small country churches to the magnificence of great cathedral windows.
By the middle of the sixteenth century, the Germans were producing tall, sturdy cylindrical glasses, known as Humpen. These were made of Waldglas and came to be lavishly decorated with enamel. All kinds of subjects were used—coats of arms, scenes from daily life, working themes connected with various guilds. Like the Venetians, the Germans were great decorators of glass, but the two styles were very different. In contrast to the delicate, artificially coloured, elaborate Venetian glass, German glass was mostly the fairly thick Waldglas, with a natural colouring of green or amber. So the Germans concentrated on painted decoration and on the developing art of wheel engraving, rather than on elaborations of the glass itself. They also developed a method of making a rich ruby-red glass, using minute particles of pure gold.
In Bohemia, thicker glass was made and this went well with wheel engraving which demanded something substantial for the wheel to cut into. Bohemian glass has always held a high position and during the Baroque period, when the popularity of Venetian glass had declined, Bohemia became a world centre for the manufacture of luxury glass. All kinds of decoration were used, but wheel engraving achieved the greatest fame.
The Netherlands became a meeting point for the various existing styles of glass. Much was imported from Venice, and from the northern centres of Waldglas which were near at hand. Their own manufacture was centred on Liege and Antwerp, and the Dutch particularly developed the style of the Römer, a drinking glass also popular in Germany. These glasses can often be seen in the detailed Dutch paintings of the seventeenth century. But gradually the Dutch turned more to decorating imported glass than to making their own, and they developed this art to a very high level. They engraved both by the copper wheel method and by diamond point. Their superb hand engraving was, and still is, without equal.
France is particularly noted for three kinds of glass development. In the Middle Ages, French stained glass windows were at their height as in the cathedrals of Chartres and Poitiers; in the seventeenth century the French not only started making mirrors but broke the monopoly of the Venetians; and towards the end of the same century they invented the first process of making plate glass. The manufacture of table glass tended to lag behind but this was offset to some extent by the establishment of the famous factory at Baccarat in 1765. This became particularly well known for the production of millefiore paperweights. France has never been a centre of applied decoration, but in modern times—from the nineteenth century onwards—much attention has been paid to design. Names to note among modern manufacturers are Lalique and Daum.
In England, glassmaking had a chequered history. During the Dark Ages, as in so many other areas in Europe, there had been very little activity: there was not much place for such a fragile luxury as glass in the uncertain and dangerous everyday life of those unsettled centuries. Around the early thirteenth century, however, when conditions were far better, glassmaking began to revive, the centre of activity being a small hamlet in the thickly wooded Weald area of Surrey, near Chiddingfold. The Weald in general was an iron producing area, but in the mid-thirteenth century an immigrant Frenchman from Normandy, Laurence Vitrearius, established himself there and became renowned for church windows, receiving orders for no less a building than Westminster Abbey and, later, for St George's Chapel, Windsor. He was followed in the same locality by two other families, one also of Norman origin, and between them they made glass in that area for over 300 years. Other glass centres existed throughout the Weald, its abundant wood fuel serving the glassmakers as it had for centuries served the ancient ironworks. Natural green-coloured Wealden glass, much like Waldglas, was produced in some quantity and acquired a considerable reputation in England.
Excerpted from Engraving and Decorating Glass by Barbara Norman. Copyright © 1972 Barbara Norman. Excerpted by permission of Dover Publications, Inc..
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