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The History of Glass V6 | Venetian Glass

Venetian Glass

By Dr Jessamy Kelly, glass artist and educator

Between the 13th and 15th century, Venice was a key route for world trade, from which it rose to be the prominent and important glass making centre it is today. A distinct style emerged that blended Roman glass techniques with skills learned from the Byzantine empire. Venetian glass experienced a golden age during the Renaissance, creating superior products that became widely copied and imitated throughout Europe.

Figure 1 Wineglass (about 1600–1699). CMoG 63.3.12. Image licensed by The Corning Museum of Glass, Corning, NY (www.cmog.org) under CC BY-NC-SA 4.0

At this time glassblowers in Venice had to be Venetian citizens and were banned from foreign travel.  In the 13th century, Glass production was moved to the island of Murano to ensure the trade secrets were kept safe and to protect the industry from outsiders. It was forbidden to divulge trade secrets. If a glassworker left the city without permission, he would be ordered to return.  If he failed, his family would be imprisoned. If he still did not return, an assassin would be sent to kill him. However, the industry was deprived of external influences which meant that the industry eventually stagnated and started to decline.

The Venetian style was widely copied and was known as Façon de Venise (Venetian fashion), a type of glass made in the style of Venetian Glass but not made in Venice itself. Often cheaper than the real thing, these imitations damaged the sale of Venetian glass.

The rise of glass as an artistic medium saw new levels of technical innovation. Early glass often had a colour-cast caused by impurities, such as metallic oxides, in the raw materials. As such clear glass was highly sought after. Venetian glass evolved to be blown very thin, effectively diluting the colour cast, and making it look clear. A major breakthrough came in 1450 when Angelo Barovier developed Cristallo glass. Cristallo is a nearly colourless glass which emulated rock crystal (see figure 1). It was usually combined with opulent decorative techniques such as enamelling and gilding which were painted on top.

Also of interest, is this fine example of a filigrana wine glass made from a delicate case of white glass canes on a thin layer of cristallo. This wine glass is known as the Rosenborg type, it was made for the Danish king, Frederick IV and were sent to castle Rosenborg (see figure 2).

A true feat of Venetian glass making is this 17th century dragon-stem goblet which has a serpent with wings for its stem. The style has its origin in the Baroque period (see figure3). Glass artist Bill Gudenrath, is one of a few contemporary craftsmen who have perfected this technique; watch an online demonstration of Bill making a dragon-stem goblet at the Corning Museum of Glass, in America.



Figure 4. Bowl (1600–1699). CMoG 9.3.1108. Gift of the Ruth Bryan Strauss Memorial Foundation.Image licensed by The Corning Museum of Glass, Corning, NY (www.cmog.org) under CC BY-NC-SA 4.0

The Renaissance saw a mania for hardstones such as chalcedony, agate, jade, jasper, bloodstone, prase, topaz and lapis lazuli spread across Europe. Venetian glassmakers began to imitate these materials in their glass creating intricate, coloured effects. This Calcedonio bowl is in the collection of the Corning Museum of Glass and is also known as agate glass. It is an excellent example of this technique which sees a light opaque background mixed with warm and darker tones of coloured oxides creating the streaky agate, or quartz-like, effect (see figure 4).

Highly innovative, the Venetian glassmakers experimented with Roman glass techniques, a range of typical Venetian glassblowing techniques developed from what was known as mosaic glass. Renowned for decorating their glass vessels with brightly coloured cane and fine filigree. Techniques such as millefiori (thousand flowers) were created. Multi-coloured glass rods were bundled together, rather like spaghetti, fused & then stretched to make to make a new rod with the pattern. A similar process to extruding making sweets such as sticks of rock.  Slices were then cut off, assembled to make a  pattern & fused together to create a sheet of glass which could be rolled up into vessel forms containing a pattern of tiny delicate flowers (see figure 5). These techniques survive today and are widely practiced in the studio glass community.

Next month we will look at the development of crystal from 17th and 18th century, with early examples from Germany and Bohemia and the development of lead crystal by George Ravenscroft in London, in 1674.

By Dr Jessamy Kelly

Jessamy Kelly is a glass artist and educator based in Edinburgh, she has worked as a freelance glass designer for Cumbria Crystal since 2016. She is the designer of the Loop and Palm collections.


Do you have any questions or feedback? We would very much like you to share by emailing verity@cumbriacrystal.com

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The History of Glass V5 | Byzantine Glass

Byzantine Glass

By Dr Jessamy Kelly, glass artist and educator

This month we will discuss the epoch of Byzantine Glass from the Middle East, which saw an elevated demand as high-end, luxury objects spread around the world, widely dispersing Islamic glass through trade.

Figure 1 Glass flask, blown glass, 4th–6th century A.D. Early Byzantine, Roman, Syrian. Image courtesy of the Met Museum.

After the fall of the Roman Empire, Western glass making was seriously affected. However, in the East, highly decorative glass continued to flourish with a range of mosaics, kiln cast and blown glass vessels produced during this period.

The Byzantine Empire was the continued legacy of the Roman Empire in the East during late antiquity (284AD-700AD) into the middle-ages (5th– 15th century). Constantinople, known today as Istanbul, was the capital of the Roman Empire, in Turkey. When considering Byzantine glass from this period, it is apparent that there is a superfluity of technique and process.

During the 9th century decorative techniques were pioneered, including metallic stains which created a lustre. Into the 10th & 11th century cast and cut vessels were improved upon with some very fine examples created. Between the 12th and 14th centuries gilding and enamelling techniques were pioneered, creating beautifully ornate designs on the glass.

Byzantine glass makers were based in the Levant, better known today as Syria and Palestine. They worked in a distinct style, notable examples from this period include glass drinking flasks that have a u-shaped mouth, where the mouth of the bottle is like a cylindrical funnel usually with fine threads of glass wound around the neck, often with handles to aid pouring (see figure 1). Or, a swan shaped neck, where the delicate neck of the bottle is twisted back (see figure 2). These are often called ashkdans and were apparently for collecting the tears of wives whose husbands were fighting wars. 

Mosaics were a huge part of the Roman Empire and exceptional examples were created during the Byzantine period. Mosaics are images or patterns created from numerous small pieces of coloured stone, glass or ceramic set with mortar and were often used as floor or wall decoration. This beautiful panel (see figure 3) is a mix of marble and glass tesserae. It depicts a woman with very detailed jewellery holding a measuring tool, with a man offering a cornucopia to her left. The piece was restored by the Met Museum and is held in their collection.

Our final example is a beautifully enamelled and gilded glass candlestick. The surface is completely covered in Islamic geometric patterns, which include hand-painted hexagons and stars that encircle the piece (see figure 4). It is a fine example of Mamluk art from the late 14th and 15th centuries, the inscription on the piece is dedicated to a Mamluk sultan. The Mamluk capital Cairo, became a centre of trade in the Islamic world which created an economic, cultural and artistic hub.



Figure 4. Candlestick, enamelled and gilded blown glass, probably Egypt, about 1340-1365. Image courtesy of the Corning Museum of Glass.

Next month we will look at Venetian Glass from the 15th-17th Centuries, a style emerged that blended Roman glass making techniques with skills learned from the Byzantine Empire. Located at the European end of the famous Silk Road, which stretched all the way to China, Venice became a great trading centre and the most important glass-making centre in the world.

By Dr Jessamy Kelly

Jessamy Kelly is a glass artist and educator based in Edinburgh, she has worked as a freelance glass designer for Cumbria Crystal since 2016. She is the designer of the Loop and Palm collections.


Do you have any questions or feedback? We would very much like you to share by emailing verity@cumbriacrystal.com

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The History of Glass V4 | Medieval glass

Medieval glass

By Dr Jessamy Kelly, glass artist and educator

This month we are looking at Medieval Glass from the middle-ages, which has a wide spanning history from the fall of the Roman Empire (5th century A.D.), when many glass-making techniques were forgotten or lost, until the rise of the Byzantine Empire. Over time many forgotten glass techniques were rediscovered and glass-making began to flourish once again, alongside luxurious glass imported from the Middle East, with a number of outstanding historical examples worthy of discussion.

Figure 1 Reconstructed stained glass made from excavated glass from St Paul’s Church, Jarrow, Courtesy of the Jarrow Hall Museum Collection

Medieval Glass usually evokes a strong image of stained-glass windows, which were the foremost pictorial art form of the time. These illuminated biblical narratives would have been hugely influential to the beholder and been central to religious life. In the 5th & 6th centuries window glass, in the form of small clear roundels, were introduced to Britain by the Romans. However, this went out of use when the Roman legions left.

In the 7th century, early pioneers in the North-East of England introduced some of the first stained-glass windows to Anglo-Saxon England – including York Minister; St Peters Church in Sunderland and the Monkwearmouth Jarrow monastery, home to the venerable Bede, an enlightened scholar of the time.

A significant example is a reconstructed stained-glass panel made from excavated glass from St Paul’s Church, Jarrow (see figure 1). The cultural significance of this piece is the likely connection with the scholar Bede, a monk at the monastery in Jarrow in the early 6th century who wrote about the Abbott Biscop who travelled to France to find specialist glaziers to fit stained glass windows into the St Peter’s Church in Monkwearmouth Sunderland.

English glassmaking is rumoured to have developed near Sunderland as the high-quality sand needed to make glass, could replace the traditional ballast used in French trading ships, creating a commercial advantage for the shippers & eventually an established trading route.

These sites are now recognised as World Heritage Sites by UNESCO. The stained glass within them would have been likely inspired by windows seen on pilgramages to France, Germany & Italy. Jarrow Hall in the North-East of England has the largest European Collection of 7th & 8th century coloured window glass from excavated finds at the site.

Moving away from architectural glass, German Wald Glass or Forest Glass stems from the late medieval period (1000-1200 AD) and has a distinctive green colour due to iron impurities present in the sand used to make it. A key ingredient in the production of this glass was potash, which came from the ashes of trees or ferns from the forest, hence the name. It was an early example of craftsman using local materials that were to hand. Decorated beakers and bottles (see figures 2 & 3) became very popular during this time. Practical in form they often had decorative trails and prunts applied by the glassblower. It is thought these motifs were added to stop the glass slipping through the hand, possibly when eating greasy foods.


Figure 4 Beaker with Lions (1175–1225). CMoG 67.1.11. Image licensed by The Corning Museum of Glass, Corning, NY (www.cmog.org) under CC BY-NC-SA 4.0

Our final example is the Hedwig Beakers, ornate drinking glasses from the 12th century. They are elaborately decorated with Christian iconography including lions, griffins and eagles however, their origin is from the Middle East. Historians suggest that they were possibly crafted by Muslim craftsmen during the crusades and were likely made for export to Europe, or for Christian clients. The glasses take their name from a Silesian princess, Saint Hedwig. Their origins are widely disputed and could be from Egypt, Iran or Syria. In total, 14 glasses of this type have been found, all have similar decorations and shape, made from a smoky grey glass with a greenish or yellowish tinge. Made to imitate rock crystal – an extremely luxurious material in the middle-ages; it is thought that they may have been part of a chalice (see figure 4).

Next month we will discuss the epoch of Byzantine Glass from the middle east spanning the 10th to 15th centuries, which were in demand as high-end, luxury objects around the world.

By Dr Jessamy Kelly

Jessamy Kelly is a glass artist and educator based in Edinburgh, she has worked as a freelance glass designer for Cumbria Crystal since 2016. She is the designer of the Loop and Palm collections.


Do you have any questions or feedback? We would very much like you to share by emailing verity@cumbriacrystal.com

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The History of Glass V3 | Roman glass

Roman glass

By Dr Jessamy Kelly, glass artist and educator

The cultural and social significance of ancient glass, is a wide reaching, rich and varied topic, this blog is a journey through glass history from ancient glass right up to present day. This month we are looking at Roman glass.

Cage Cup (probably 300-399). CMoG 87.1.1. Purchased with funds from the Arthur Rubloff Residuary Trust. Image licensed by The Corning Museum of Glass, Corning, NY (www.cmog.org) under CC BY-NC-SA 4.0

In the 1st century BC, glassblowing was developed in Syria. By AD 50 it became the leading glass forming technique completely revolutionizing how glass had been produced for thousands of years. Glass blowing is, a glass forming technique that involves the inflation of molten glass using a hollow metal pipe, called a blowing iron, to inflate a glass bubble, which can then be manipulated into a wide range of vessel shapes of varying sizes. This technique was quicker and easier than other earlier techniques, making glass vessels considerably more affordable. This was especially true when glass was blown into terracotta moulds enabling large numbers of products to be produced quickly.

Glass blowing as a technique quickly spread through the Roman Empire from the eastern Mediterranean to the west. By the 1st century AD, the Roman glass industry grew exponentially, due to a period of advanced technical growth. A range of decorative finishing techniques were developed such as gilding, enamelling and painting. Techniques were developed during this era that enabled exceptionally high-quality cut and engraved products to be produced. Cage cups, such as the Lycurgus Cup (see figure 1), were made and are a true feat of glass-cutting technology, where a thick blown glass vessel is painstakingly cut away to create a design which is connected to the wall of the vessel by small bridges hidden behind the decoration. A truly amazing example of this is the Lycurgus Cup which depicts an ill-fated king who is seen being strangled by vines after taunting Dionysos, the ancient Greek God of wine. What is particularly of note about this cup is that it is made from dichroic glass, where small nano-particles of gold and silver are mixed into the glass so that it changes from a green colour when lit from in front, to red, when lit from inside or behind the cup.

Around the turn of the 1st century BC/AD cameo cut glass vessels were introduced, the most famous example of this style being the Portland vase, which is housed in the British Museum, London (see figure 3). This vase is an excellent example of Roman cameo glass, a hot glass bubble of one colour glass was encased in an outer layer of another colour. Once cooled the outer layers were cut away to create a design in relief. The most common colour scheme of Roman cameo glass was opaque white over transparent dark blue.


Renowned for their love of feasting, Roberto Bompiani shows his extensive research into a range of ancient artefacts in this painted feast scene (see figure 4). The authenticity of the painting is supported by research of the frescoes, marble, tables, lamps, and vessels all were drawn from Greek, Roman, and Etruscan sources. An intricate footed glass bowl and large drinking vessels are part of this opulent scene, which indicates the social context and frivolity of this feast and the use of glass; which is something which we can all connect with – socialising with friends over fine wine and food. As a form of storytelling the painting brings these historical artefacts back to life and makes us think about their significance and meaning.


Figure 4.  A Roman Feast by Roberto Bompiani (late 19th century), oil on canvas. Courtesy of the J. Paul Getty Museum.

Next month’s newsletter will introduce Medieval Glass, from AD 400-1066, including green forest glass and some outstanding examples of Medieval stained glass.

By Dr Jessamy Kelly

Jessamy Kelly is a glass artist and educator based in Edinburgh, she has worked as a freelance glass designer for Cumbria Crystal since 2016.


Do you have any questions or feedback? We would very much like you to share by emailing verity@cumbriacrystal.com

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The History of Glass V2 | Hellenistic Glass 325 BC – AD 400

Hellenistic Glass 325 BC – AD 400

By Dr Jessamy Kelly, glass artist and educator

Examining the many facets of a glass artefact and imagining the stories it can tell can be an inspiring and evocative experience. Ancient glass artefacts can act as bridges to the past, by understanding how they were made and used and the unique social and spiritual values they embody.

Figure 1. Glass mosaic ribbed bowl late 1st century B.C.–early 1st century A.D. Image courtesy of the Met Museum

This series of articles can be viewed as a gateway through which to navigate the cultural significance of glass through time. This month we are delving into the Hellenistic period, a rich and colourful chapter of ancient glass history, which includes the years between the reign of Alexander the Great and the early years of the Roman Empire. Glass artefacts from this period can be traced back across a wide span of regions from the Mediterranean to Europe, Western Asia and Northern Africa.

Much of the glass produced during this era predates glass blowing, the style is exemplified by the process by which glass vessels were produced using a kiln[1]. Key techniques such as mosaic glass became the hallmark of this period, fairly large bowls and platters created from colourful canes of glass. The canes were laid into a mould and then heated in a kiln so that they became fused and slumped together to form a colourful mosaic. The vessels were made up of many small spirals and stars arranged in a range of bright or mono-chromatic glass colours (see Figure 1).

A further example is lacework or reticella glass, which was created from spirals of twisted glass canes known as tesserae which were assembled next to each other to form intricate patterns (see Figure 2). Mosaic glass was a highly sophisticated technique, the main drawback was the labour, as it was extremely time consuming to form and polish the glass. Over time, it was replaced by glass blowing which was much more efficient. Today, fused glass has evolved from this origin to be a wide and highly technical subset of kiln forming.


[1] an oven or furnace used for processing glass by high firing it in a mould, kilns are also used in pottery.

Figure 2. Lace Mosaic Bowl, Roman Empire, Italy, 225-100 BCE. Image courtesy of the Corning Museum of Glass

A topic close to many of our hearts is wine. The cultivation of grapes for wine making, predates the Hellenistic Age, but during this epoch it became widely popularised and many glass drinking vessels were made for lavish social events that focused on drinking and feasting. This Levantine wine cup was an early kiln formed example, the glass would have been placed in a wooden foot as the disc shaped based would have been unstable (see Figure 3). The base would have been very useful and connects us to a universal concern that we may damage our glasses through use.

Figure 3. Levantine, Amber glass wine cup, moulded glass, Levant (modern day Syria) (ca. 100 BC-AD 100). Image courtesy of the Allard Pierson Museum, Amsterdam.

The final artefact for your consideration is a mythical story from a Persian poem about Alexander the Great, who had a diving bell made out of glass (see Figure 4).  

An elaborate, rather comical story was told of how curious Alexander was of the sea and how he was lowered down in his diving bell along with a dog, a cat, and a cock to explore the ocean. He entrusted his wife with the chain that could pull the bell back up to the surface, unfortunately she eloped with her lover and threw the chain away, so he had to devise his own escape. Many stories were written about Alexander to document his daring and outlandish exploit, this story resonates for me because of the period from which it originates, in that it centres glass as an innovative material and makes the impossible seem possible, could this really have happened?

Figure 4. Alexander the Great under Water by Jansen Enikel, Regensburg, Bavaria, Germany. Tempera colors, gold, silver paint, and ink on parchment, about 1400 – 1410, Courtesy of the J. Paul Getty Museum.

 

Next month’s newsletter will introduce Roman Glass, during the 1st century AD the Roman revolutionised the glass industry with the introduction of glassblowing, establishing glass as a widely available and popular material for vessels.

By Dr Jessamy Kelly

Jessamy Kelly is a glass artist and educator based in Edinburgh, she has worked as a freelance glass designer for Cumbria Crystal since 2016.


Do you have any questions or feedback? We would very much like you to share by emailing verity@cumbriacrystal.com

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The History of Glass V1 | Ancient Mesopotamia & Egyptian Glass – 3000 – 1000 BC

Ancient Mesopotamia & Egyptian Glass – 3000 – 1000 BC

Figure 2. Portrait of King Amenhotep II, Egypt, 1426-1400 BC. Deep blue glass with light tan surface. Collection of the Corning Museum of Glass, Corning, NY (79.1.4).

By Dr Jessamy Kelly, glass artist and educator

Humans have made glass for over 5000 years and over time glass objects have shaped and changed human history. Glass is a material that people have worn as amulets, beads or jewels, traded, exchanged and longed after. They have drunk and ate from glass, the have cooked with it, they have treasured it, looked through it as windows or eyeglasses and into it as mirrors.

Figure 2. Portrait of King Amenhotep II, Egypt, 1426-1400 BC. Deep blue glass with light tan surface. Collection of the Corning Museum of Glass, Corning, NY (79.1.4).  

 
In more recent years, it has become apparent how the invention of glass has fundamentally changed humankind. In the 17th century, glass was pioneered by alchemists who first used it for their experiments, glass has led to many great scientific discoveries. Since then many great innovations have been made, from optical glass for lenses, microscopes and telescopes to test tubes, light bulbs, fibre optics, mobile phones and televisions. Finding ways to access the cultural values and significance of glass as a material over time brings the history of these objects into a new light. When handling and using glass in our everyday lives we can make a connection to the history of glass and the interesting stories it tells through its use. This series of articles, will introduce the history of this beautiful medium, providing a deeper understanding of how glass is made in both an historical and contemporary context.

“There is a story that once a ship belonging to some traders in nitrum* put in here (the coast of Lebanon) and that they scattered along the shore to prepare a meal. Since, however, no stones for supporting their cauldrons were forthcoming, they rested them on lumps of nitrum from their cargo. When these became heated and were completely mingle with the sand on the beach a strange liquid flowed in streams; and this it is said, was the origin of glass”. (Pliny, Natural History, xxxvi, 191-2.)

This quote is from a roman naturalist named Pliny the Elder, who explained the invention of glass in the second half of the first century AD in his book Natural History. However, we now know that glass was actually made well before this. The origins of glass can be traced back to ancient Mesopotamia (3000 to 1000B.C) which is known today as the Middle East, and includes modern day Iraq and northern Syria. This article will introduce some of the earliest forms of glass, which can be traced back to ancient Mesopotamia and Egypt.

Egyptian faience dates from around 4000 B.C. it is a ceramic material made from sand or quartz, when fired a very colourful glassy surface is created. It was usually formed into beads, rings, amulets and statues that resembled semi-precious stones such as lapis lazuli and turquoise (see figure 1). They were seen as magical objects, instilled with the powers of rebirth and the bright colours were connected with the intense radiance of eternity. This funerary collar was used for burial, similar bracelets and anklets were found within the Tomb of Wah, in Thebes.


Figure 1. Broad Collar of Wah, Faience, linen thread, Egypt, early Middle Kingdom, Dynasty 12, (40.3.2). Collection of the Met Museum

Figure 1. Disk Pendant with Star Pattern, cast glass, Northern Mesopotamia, 1500-1200 BCE, Collection of the Corning Museum of Glass, Corning, NY (63.1.26).

One of the earliest examples of glass, is a cast glass pendant which has an eight-pointed star (see figure 3, left) which has been traced back to Northern Mesopotamia, 1500-1200 BCE. The star pattern is connected to the goddess Ishtar, who is often associated with the goddess of love and war. The process is called glass casting and predates glassblowing, it is often how solid glass objects are made, pieces of broken up glass ‘cullet’ are put into a mould and then fired high.


Figure 3. Disk Pendant with Star Pattern, cast glass, Northern Mesopotamia, 1500-1200 BCE, Collection of the Corning Museum of Glass, Corning, NY (63.1.26).

One of the earliest known portraits to be made in cast glass is the head of Amenhotep II, a Pharaoh who ruled Egypt 1426–00 bce (see figure 2, at the top of the article). Glassmaking was introduced to Egypt during the reign of Thutmose III (the father of Amenhotep II). Most likely glass makers were captured during the Egyptian expansion into the Middle East and brought back to Egypt to make glass and share their secrets.

Egyptian perfume bottles and vases are among the first examples of core formed objects, a process which also predates glass blowing and reached its zenith by the 18th Dynasty. Glass objects were formed around a soft ceramic core; the ceramic is then removed leaving a hollow glass form. The colour of this object imitates the semi-precious stone turquoise, with the yellow and white decoration representing gold and silver (see figure 4, left).


Figure 4. Vase, 18th Dynasty, 1400-1300 B.C. Egypt Turquoise & opaque cobalt blue, yellow, white, with translucent cobalt blue; core formed, trail decorated. H. 10.7cm. Collection of the Corning Museum of Glass, Corning, NY (66.1.213).


Next month’s newsletter will introduce Glass from the Hellenistic period, which includes the years between the reign of Alexander the Great and the advent of the Roman Empire.

By Dr Jessamy Kelly

Jessamy Kelly is a glass artist and educator based in Edinburgh, she has worked as a freelance glass designer for Cumbria Crystal since 2016.


Do you have any questions or feedback? We would very much like you to share by emailing verity@cumbriacrystal.com


* nitrum is an alkali such as soda ash, which is a material used to make glass.