Making: Lampwork Glass Beads

What is Lampwork

Lampwork is a type of glasswork used to create smaller glass objects using a fixed directional flame to melt the glass, whilst using lamp working tools and gravity to shape the piece. It is a very different process from glass blowing which as the name suggests uses a blowpipe to inflate a glass gob or gather to form a cylindrical glass shape which can then be shaped with glass blowing tools. These small handcrafted lampwork pieces are the most time consuming method of making glass beads as each art bead is individually made over a flame, resulting in labour intensive but beautifully bespoke one of a kind beads.

A Brief History of Lampwork Glass Bead Making

Lampworking is the result of a combination of chance – that first piece of natural glass falling by accident into an open fire – alongside a long history of innovation, development and refinement. It is impossible to really determine when lampworking as a process was born but many of the elements that make lampworking what it is today can be traced back through the centuries to when mankind first discovered how to make glass.

Through archaeological excavations and examination of early glass artefacts it is known that small open fires were used for all forms of early glass making. In time small earth formed beehive furnaces were introduced. These primitive furnaces are known to have been used in ancient civilizations from Japan to North Africa, and seem to have dominated glassmaking prior to the birth of Christ. It was the Romans who took this basic beehive shaped furnace and refined it with the addition of exhaust vents and side access, creating what would effectively become the first true glass furnace. Alongside this they also developed and refined new glass working tools for shaping the glass that they produced. Glassmaking became a sophisticated and highly successful industry during Roman times, with 600 years spent refining their techniques until they were adept at shaping glass, colouring glass, recycling glass and even more impressively removing colour from glass until it was almost clear.

The next significant phase in glassmaking followed the sacking of Rome in the 5th Century and the rise of Islam and the exquisite artistry that this culture embodied. It is in the 10th Century, specifically 982AD, that the first recorded reference is found to Venetian glassmaking. In the 13th Century Byzantium was captured by the Franks and the Venetians, with Islamic glass making techniques quickly adopted within Venice’s established glass making industry. The epicentre for glass making had now moved to Europe. As Venice’s glass making industry moved from strength to strength it benefited from the Republics status as a major trade centre for Europe, Asia and North Africa. Keen to keep their competitive edge the Venetian authorities introduce protectionist measures banning the import of foreign glass, whilst ensuring Venetian glassmakers were discouraged from disclosing their techniques by moving their foundries to the isolated Island of Murano in the Venetian Lagoon. To read more about this particular region and its intriguing history have a look at our History of Venetian Glass Making in our Guides & Information section on our website or on this blog.

Times have now changed, and tourists are encouraged to visit the original glass furnaces and workshops on Murano to see how the workers create glassworks using methods unchanged for hundreds of years.

Following the continuing dominance of Venice in glass manufacturing and the pivotal moment Angelo Barovier invented cristallo clear glass in 1450, we jump forward to the early 17th century to find French, Germany and Italian glassworkers using the flame of an oil lamp or spirit lamp to heat and manipulate small quantities of glass. The glass workers would raise the temperature of the flame tip by blowing air into it through a narrow pipe or tube. This would generate sufficient heat to melt the softer types of lampwork glass rods available to them. So this is where the lamp in lampwork originated from, providing the first significant parallel between historical glass manufacturing and modern lampworking today.

Working in a hot environment this lampworking technique proved less than ideal as workers were unable to blow into the pipe or tubing consistently for any length of time without experiencing dizziness, or passing out through lack of oxygen! The first much needed refinement to this process was a hand blower, or hand bellows, as illustrated in the plate below. Although this was a significant improvement it had two drawbacks – it required one hand to operate the bellows and it lacked a mechanism to ensure a consistent flow of air to the flame. Simply put the bellows had to be released in order to refill them with air for the next pump. 

This plate depicts an early hand pumped lampworking device entitled Fletcher’s Leather Hand Blower and Lamp (Source – Traditional Glassworking Techniques by Paul N Hasluck)

The next development introduced a foot operated bellows which freed up the workers hands so that they could again be focused on shaping the glass, but it still lacked a mechanism to drive a consistent flow of air through to the flame, without which a uniform temperature could not be focused on the heated glass. 

This plate shows a foot bellow operated lampworking bench (Source – Traditional Glassworking Techniques by Paul N Hasluck)

The final refinement needed was an expandable bladder attached to the foot bellows which meant air could be stored prior to being pushed through to the flame, giving a more consistent flow of air to the flame. This would give the lampworker the ability to selectively heat areas of the glass object being worked on, bringing greater refinement and accuracy to the process. With the bladder system in place this lampworking process proved more economical and energy efficient, whilst allowing for greater intricacy and detail than could ever be achieved by glassblowing. It essentially brought down prices for glass objects and placed them within the reach of a far wider customer base.

It is worth noting, in the plate below, that the lamp working industry employed both men and women and that this was particularly evident in Venice at the peak of production in the1800s. Women would be employed to add the decorative elements to Venetian glass Trade Beads destined for Africa and the Americas. The bead cores were still produced in an industrial, male dominated environment centred around large hot glass furnaces, but the glass decoration and detail would be added later. This task was undertaken by home workers, most of whom were women, paid on a piecemeal basis to use an oil or spirit lamp to re-heat the beads whilst adding strings or dots of coloured glass.

This plate depicts a group of male and female 17th century lampworkers at their foot bellow operated workstations. Complete with bladder system, a heat draw or extractor above the table and a detail showing the lidded flame housing which plugged into an air outlet in the table. It also shows the tongs used to shape the beads (Source – The Corning Museum of Glass)

Following the fall of the Venetian Republic to the Austrians in 1797, Venetian glass production went in to sharp decline. With Austrian backing the region of Bohemia started its rise as the new centre for glass making in Europe, a subject which is covered in greater detail on our website in our History of Czech Glass Beads or on this blog. That is until the mid 19th Century when Venice regained it’s independence and a new breed of glass maker reinvigorated Venetian glass production. They took their inspiration from Murano’s golden period and by rediscovering long forgotten glass making techniques they brought new life to the furnaces of Murano. This takes us neatly to the turn of the 20th Century when events takes us across the Atlantic to America, albeit via Germany.

In 1893 borosilicate glass was invented by German chemist Otto Schott who founded Schott AG in the same year. This revolutionary product was made from silica and boron oxide which in combination formed a very stable glass with good workability and high thermal shock resistance. It was manufactured under the name Duran and for a time was very successful. However, during the First Word War, the arrival of Pyrex from America provided a non German alternative for patriotic English speaking consumers and Pyrex soon becaming a generic term for this type of glass. Pyrex was derived from Nonex glass which was developed in 1908 by Eugene Sullivan, Director of Research at Corning Incorporated Glass Works in New York. This was a borosilicate low-expansion glass initially used to reduce breakages in shock-resistant lantern globes used on the railways as well as battery jars. In 1913 Jessie Littleton, a scientist working at Corning realised this glasses potential for cookware, when he gave his wife an oven proof dish for cooking with. By removing the lead from the Nonex glassmaking process Pyrex was born – some 20 years after Otto Schott first introduced the world to borosilicate glass!

A good 15% lighter by volume and much stronger than soda based glass, Pyrex became an immediate success as a consumer bakeware product as well as for laboratory ware and telescope lenses. However, its melting point was so high that existing oil lamps could not melt the glass and so the material could not be easily worked. With the glass industry having always been innovative it looked to the welding trade for a solution. In time, by combining oxygen and natural gas, new burners were designed that produced a flame of sufficient heat to melt Pyrex glass rods. These flameworking torches quickly replaced traditional oil lamps both in mainstream production and at the workstations of glass artists and artisans who quickly adapted this new glass for artistic and novelty lampwork glass pieces.

In Europe, and in particular Czechoslovakia, Italy and Germany soda glass remained the norm as did the old techniques that had ably supported this industry for centuries. However, history has shown that they were not adverse to adopting techniques and innovations when needed and they were quick to see the benefits of the new gas burning torches in place of their now outdated oil lamps. So for many years glass making skills remained squarely in the Old World whilst the New World pushed forward with technological developments in glass production and factory automation. That is until some 25 years ago when the playing field was levelled somewhat by a group of American glasswork artists who, having either visited the foundries in Murano or been influenced by European glassworkers living in America, sought to recreate what they had seen. Although hampered by the secrecy and fear of competition that still shrouded lampworking production in Europe they used experimentation, documentation and collaboration to progress from initially crude lamp work beads to the levels of art glass lampwork that is evident today. Alongside the growth in their abilities came new glass bead making tools, glass torches and other equipment and lampwork supplies which were tested, developed and put into production. This contemporary lampworking collective eventually formed the nucleus for the International Society of Glass Beadmakers.

Lampwork Bead Making Today

With much credit afforded to the aforementioned group, lampworkers throughout the world have become recognised in their own right as artists and many galleries now exhibit lampwork glass – displaying the lampworkers individual creativity, style, technique and understanding of colour. Their work is shown and sold alongside the more traditional mediums of glass blowing and casting, as well as painting and sculpture, in the art galleries of Europe, Japan, and the United States. With the growth of the internet those with shallower pockets can also buy artist made lampwork bead sets from independent bead making artists, often sold through their own web sites, or through online market places such as Etsy and Artfire. At the bottom end of the scale you can also buy lampwork beads that are mass produced in India and China – just don’t expect to create one of a kind jewellery with that unique focal point that artisan lampwork beads can give to a jewellery design!

BigBeadLittleBead offers a selection of over 250 one of a kind lampwork glass beads for you to choose from, created by our own talented lampwork glass bead makers. For those that are working to a tight budget we also stock a selection of Chinese lampwork beads and Indian lampwork beads.

Lampworking Torches

As touched on earlier the lampworking process today is almost unchanged from centuries gone by, with a flame still the only method used to melt the glass rods. The principal difference today lies in changes to the delivery of the flame, with modern lampwork bead makers using single or dual fuelled torches clamped to their workstations. Most lampwork artists use a bead making torch that burns either propane or natural gas for the fuel, surface mixed with air or pure oxygen (either from a tank or a lampwork oxygen concentrator) as the oxidiser. This creates a cleaner and quieter flame. It is this change that has seen lampwork sometimes referred to as flamework, and in turn lampworking as glass flameworking. Some lampwork torches can also be run from portable gas canisters but these are usually only used by hobbyists or for demonstration purposes.

The image above shows a very tidy lampworkers workstation or bench with everything within easy reach

Lampworking Glass

The most common glass used today remains soda lime glass or soft glass and as a basic material it is no different to the Cristallo glass developed by Angleo Barovier in the mid 15th century and used by glassworkers from then onwards. This glass melts at a relatively low temperature allowing the bead to be kept warm whilst being manipulated reducing the possibility of cracking. The other option is Borosilicate glass, also known as boro glass or hard glass, which as we have seen originated as a laboratory glass, but is now also used for lampworking. Both of these glass types have their own merits depending on their application. The principal benefit of soft glass is its melting point, however it does not react well to temperature changes in the way that boro glass does. Because soft glass expands far more than hard glass when heated, and contracts more when cooled, it is far more prone to cracking through thermal shock. If, for example, a section of a bead cools too quickly that point will solidify faster than the surrounding glass causing a radial crack. Hard glass, or borosilicate glass, would be more resilient in this example. It is considered to be far more forgiving to work with, but on the downside it has a narrower working temperature range than soda-lime glass, fewer colour options, and borosilicate glass rods are more expensive to buy. In addition, its higher working temperature range means a larger and subsequently more expensive lampworking torch is needed. Typically this will use oxygen rather than air to work the glass because of its higher melting point, bringing added costs and some additional safety factors.

The image above shows a selection of soft glass rods in a variety of colours and thicknesses

Basic Lampwork Bead Making Tools And Materials

There are many lampwork bead tools and presses available for shaping hot glass to produce a variety of complex shaped beads. These are commonly made from brass or graphite to avoid the glass sticking to the tool face.

The image above shows a small selection of the tools available to the lampworker all presented handle first for ease of use

Although now more sophisticated in their use of technology and materials, many of these flameworking tools are simply re-workings of the tools that were used widely in Murano and elsewhere in Europe for centuries. Time has shown them to be the most effective way of manipulating and shaping glass. The following list details a core set of tools for the lampwork beginner, which as you become more experienced will open your eyes to additional lampwork tools and lampwork supplies based around the designs you want to make.

• Torch – There are many models on the market with the innovative Nortel Mega Minor gaining good reviews with its useful torch mounted marver. Ultimately the choice depends on your budget, your skill level and the glass that you will be working with.
• Mandrels – These stainless steel rods are the base upon which glass is wound to form a bead. The diameter of the bead mandrels determines the size of the bead hole. Various sizes are available but for a beginner a 2.4mm mandrel is recommended. There are much larger mandrels for lampworking available but they get heavier as they get larger. As you improve you can reduce the mandrel size to create beads with smaller holes.
• Bead Release – A clay like substance which the lampwork mandrels are dipped into to prevent the glass sticking to the steel mandrel.
• Goggles – Protective eyewear. Didymium lens safety lampworking glasses are essential.
• Marver – A graphite or brass paddle originating from the French word marver which translates as marble. This heat resistant surface is used to roll, press and shape hot beads. Marvers can be flat or patterned.
• Glass Rods – Moretti Effetre glass, CIM glass, Bullseye glass and Lauscha glass are four of the more popular manufacturers of glass lampworking rods but there are many others brands of glass rods for bead making available. Their diameters vary but should not usually exceed a quarter of an inch for bead making glass.

You should also make use of one of the following bead cooling products:

• Vermiculite – A natural mineral that expands when heated. A large bowl filled with vemiculite pieces can be used to gradually cool warm beads.
• Japanese Annealing Bubbles – Tiny, hollow micro spheres made from silica again place in a large bowl they can be used to gradually cool warm beads.
• Fibre Blanket – Made from insulating ceramic fibres these blankets are used to gradually cool warm glass beads.
• Temperature Ready Lampworking Kiln – This large kiln like container can be used to gradually cool warm beads.

If you intend to sell your lampwork beads it is important to anneal your pieces in a kiln to ensure strength & durability. Beads should be heated to between 940º-1050°F (depending on the glass type), until the glass reaches its stress relief point. It should be held at this temperature for a short time before being slowly cooled to avoid thermal shock. The annealing process will result in a lampwork piece that will last for many years and be durable enough for everyday wear. Glass which has not been annealed may crack or shatter following seemingly minor temperature changes or shocks.

It is also essential that you work in a well ventilated room and are safety conscious.

Basic Lampwork Glass Bead Making Tutorial

• Prepare a mandrel by dipping it into the bead release to a length of about 6cm and then leave it to dry. A 2.4mm mandrel is a good starting size for beginners
• Take a rod of glass in your right hand and gently warm the tip by slowly introducing the rod into the flame. Rotate the rod whilst you are warming it to ensure an even heat. When you have a glow at the end of the glass rod carry on until you have heated a pea sized molten ball of glass

• Take the prepared mandrel in your left hand and heat it in the flame to an orange glow. If the mandrel is not warm enough the glass will refuse to stick to the mandrel

• Place the tip of the molten glass rod on the mandrel and wrap the glass on to it, rather like winding thread onto a spool. Keep turning the mandrel away from your body

• The glass that has been wound onto the mandrel will be glowing orange so take the mandrel out of the flame, moving it away from you whilst keeping it level. Let the glow dim. To make the bead larger return it to the flame and heat it again until glowing then add another wrap of molten glass. This will form a disc like shape prior to the glass melting down into a round bead. Continue adding the glass in this way until you have the size of bead you require

• Take the bead out of the flame. It is best practice to just lower the mandrel towards the worktop remembering to keep the mandrel horizontal. Keep turning it and the glowing orange hot glass will shape itself by means of gravity. Don’t forget to keep the mandrel level otherwise the bead will become lopsided. When the bead has cooled slightly and lost its glow place it into your chosen cooling medium – the bead annealing kiln, annealing bubbles, fibre blanket, or vermiculite. Be patient and do not be tempted to examine the bead for at least 45 minutes as it will be very hot!

• When the bead is cold remove it from the mandrel, clean out the bead release, wash it, dry it and admire it!

When you have perfected making round handmade lampwork glass beads you can start to add surface effects by decorating each bead with stringers using fine glass rods creating lines or dots on the surface. Cold working can also be employed. This includes such techniques as sandblasting, faceting, polishing, as well acid etching the finished piece to leave a matte sea glass like finish. The design and decorating possibilities are endless – limited only by the skill and imagination of you as the lampwork beading artist!

As you get more adept you can explore other lampwork flame techniques, for example, layering different colours of glass to create depth and pattern, adding inclusions into the beads such as silver, gold or copper leaf, melting and racking lampwork frit across the surface of the beads, or creating hollow lampwork beads. Adding enamels, imitation gemstones or small flowers called millefiori are also popular. Lampworking can also be used to create other types of artwork, including lampwork figurines, trinkets, curios, floral lampwork, Christmas tree ornaments and much more. You will also find lampwork bead classes, usually run by local lampwork bead artists, in most regions of the country.


Lampwork Glass Bead Resources

Corning Museum of Glass – Based in America this glass museum houses 45,000 glass objects tracing the history of glass across 3,500 years as well as being home to the Rakow Research Library

International Society of Glass Beadmakers – An international organisation dedicated to promoting the growth and recognition of glass bead making and lampwork artists

National Glass Centre – Based in Sunderland, England this glass museum and information centre works alongside the University of Sunderlands Glass & Ceramics Departments

Self Representing Artists – A global glass artists group dedicated to the art of lampworking and lampwork beading

Glass Beadmakers UK – Information, lampwork tutorials, links and pictures illustrating the skills of lampwork glass bead artists in the UK

Lampwork Glass Bead Further Reading

Complete Book of Glass Beadmaking by Kimberley Adams – A superb guide to inspire bead and glassmakers of all levels with detailed instructions and step by step imagery for successful lampwork beading

Creative Lampwork by Joan Gordon – History of lampworking, safety and materials, bead shapes, how to make lampwork beads, and decorative lampwork techniques

Glass Bead Jewelry Projects by Nelli Rees – A resource for those who want to make glass beads and art glass jewellery from lampwork focal beads, lampwork bracelets, lampwork necklaces to lampwork pendants

Making Glass Beads by Cindy Jenkins – Step by step glass bead making tutorials and lampworking instructions to help create handmade glass jewellery

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The content for a large part of this post was supplied by lampwork artist Lesley Silver of Beadsashore - one of our Talented Bead Makers

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Glossary: Venetian Glass

Murano’s glassmakers held a virtual monopoly on quality glassmaking for centuries and as such it remains the longest lasting centre for glass making in history. During this time they developed, or procured and refined, many processes which we have made reference to in our History of Venetian Glass guide. This glossary describes the individual process, some of the science involved and who the technique or process can be attributed to.


Aventurina (also known as Aventurine or Adventurina)

This process involves adding micro particles of copper, gold, or chromic oxide to molten glass after which deglassification, during the cooling stage, results in the separation of the particles from the molten mass. This produces an affect whereby the fine particles are suspended in the glass and appear like gold flecks when they catch the light.

The root meaning of this word is sometimes wrongly ascribed to avventura (or adventure in Italian), rather than the correct ventura (fortune or chance in Italian), but both descriptions give a good idea of the skilled nature of producing consistent pieces.

This process was a closely guarded secret when first developed and refined in the 15th Century, coming back to prominence in the mid 19th century at the glass works of Pietro Bigaglia and then Salviait & C. It is used for beads, vases, and a variety of other objects.

Image: Vintage orange and black Aventurina glass beads.

Battuto (meaning struck or beaten)

This is a cold working finishing treatment using a grinding wheel to mark the surface of the glass. The grindings are made to differing depths and with overlapping irregularity to create a faceted fish scale or hammered metal effect. This is a similar process to incisio but with broader, flatter cuts, as opposed to narrow and deep markings. The process originates from the early 1900s, most notably from the Daum glass works in Nancy, France. In Murano the process was a favourite of Carlo Scarpa at Venini & C., as well as Alfredo Barbini, Lino Tagliapietra, and Davide Salvadore.

Image: Battuto finish vase in green by Carlo Scarpa for Venini & C., circa 1940.

Calcedonio

This process results in glass that looks like the semi precious gemstone agate. This quartz stone is characterised by veins or bands of differing colours and this is replicated in this glass making technique. It is produced by mixing colouring agents, generally copper, iron, cobalt and tin oxides, with metallic silver. This is then blended into a fusion of different types of glass which is then mixed further until the desired effect is achieved.

This was an historical formula from the 16th century which was then lost only to be rediscovered in 1846 by the industrialist Lorenzo Radi. It was used by Venini & C in the designs of Napoleone Martinuzzi.

Chevron (also known as Rosetta or Star)

A chevron is a bead type produced from a cane known as a Rosetta. They were drawn from a hollow cane typically with six thin layers of glass, traditionally white, blue, white, brick red, white then finally blue. This was then ground to produce patterns with five concentric stars with twelve points. The canes were chopped allowing large numbers of beads to be produced from each production run. Later, this cane was produced without the hole and Millefiori canes were born.

They were first produced in Murano at the end of the 14th century with the first reference to chevrons appearing in the inventory of the Barovier glass works in 1496. They were one of the core bead types used as Trade Beads destined for West Africa and the Americas. Like most Murano techniques of the time production processes were heavily protected.

Today, like seed beads, the production of Chevron beads in Italy is limited due to the influx of less expensive foreign beads, in this case from from India and China. The best known contemporary chevron bead makers are Art Seymour, from America, and Luigi Cattelan, from Murano, Italy.

Image: Contemporary Venetian chevron bead produced by acclaimed Italian bead artist Luigi Cattelan.

Conterie (also known as Seed Beads)

Seed beads created by the Venetian glass bead industry were initially small, opaque and round. The simplest form of beads they were produced from hollow tubes which were then chopped and re-fired for smoothness and colour. Typically sold in shanks pre-strung or by the kilo. They were used to decorate textiles and clothing, as well as for necklaces, hair combs and earrings. The peak of their production in Murano was in the early 1900s when these beads sustained the Venetian glass industry.

Today the industry is virtually non-existent in Italy, as the market is now dominated by Japanese and Czech distributors, offering a much larger selection of sizes, colours and cuts.

Coroso (meaning corrosive)

This is a cold working treatment in which the surface of the finished article is corroded by placing it in to a bath of diluted hydrofluoric acid or ammonium fluoride. The result is a rough layer on the items surface. By varying the temperature of the solution, the time in the bath, and the composition of the acid it is possible to obtain varied effects. It is also possible to mask areas of the glass surface using wax or paraffin to protect areas from the acid and to keep them bright. This technique was introduced by the French at the beginning of the 20th century and found its first applications in Murano in the 1930s in the designs of Carlo Scarpa for Venini & C., and the vases and figures of Flavio Poli for the Seguso Vetri d'Arte firm.

Image: Seguso Vetri d'Arte bowl with a corroso surface. Produced in Murano, Italy circa 1940 whilst Flavio Poli was artistic director.

Cristallo (also known as Cristallino)

A clear, highly malleable, virtually colourless Venetian glass whose discovery is attributed to Angelo Barovier in the mid 14th century. It got its name from its resemblance to natural rock crystal. Aside from its clarity the other benefit of this discovery was that it could be blown into vessels with very thin walls which saw glass move away from the heavy designs of the time.

Filigrana

A process from 16th century Murano used to make items with an opaque white or coloured glass lined core. It was achieved by laying thin rods of clear glass alongside rods of the desired colour, which traditionally would have been white opaque glass. They are fused together in the furnace and then moulded into a cylinder. After which they can then be blown and shaped. This process has three additional patterns depending on how the filaments are twisted and aligned. With mezza-filigrana, rods with one filament are used. With vetro a reticello a diamond shaped pattern is created by twisting two halves of an object in opposite directions while heating and distorting the straight lines of the filigrana rods, creating a diamond mesh pattern. Finally vetro a retortolio consists of two filaments twisted into a spiral. All the most important Murano glass factories used this technique.

Image: A clear glass mezza filigrana wine glass with grand shaft, red toned with gold, by Seguso Vetri d'Arte circa 1985.

Ghiacciato (meaning ice)

A process used to create a cracked appearance in a piece by lowering the hot glass into cold water for a few seconds and then placing the item back into the heat of the furnace. The sudden cooling of the surface area whilst the core remains molten forces a non uniform contraction of the surface causing fine cracks which are then sealed and secured by the reheating of the surface This process was in use from the 16th to the early 18th century primarily in the production of glasses, bowls and beads. It then came to prominence again in the 20th century with craquel effect glass light fixtures. Particulalry noteworthy in this regard are the chandeliers produced by Fratelli Toso in the 1930s.

Incamicato

A multilayered glass plating technique, from the 1920s, where different layers of glass are placed over each other before being incased in a final cristallo or transparent coloured layer. This process provides great flexibility in design and finished plated pieces may be a single colour or include additional processes such as sommerso. It was a process quickly adopted up by all the most important Murano glass factories from the 1920s onwards, including Venini & C., Fratelli Toso, Vetreria Artistica Barovier & C. In large pieces it can create a great visual impact and these are much sought after.

Image: Green lattimo incamiciato green glass vase with vertical stripes and applied drops. Produced by Venini & C., circa 1928.

Incisio (meaning incision)

Like battuto this is a cold working finishing treatment using a grinding wheel. In this case the lines are narrow but deep and linear in fashion. In Murano the process was a favourite of Carlo Scarpa at Venini & C., as well as Alfredo Barbini, Lino Tagliapietra, and Davide Salvadore.

Image: An orange glass stoppered bottle with horizontal inciso produced by Paolo Venini for Venini & C. circa 1950.

Inclamo

Is the process of fusing together many different pieces of coloured glass while pliable and then forming them into a single object usually a vase or goblet. It originated in the Islamic world before being adopted and adapted in Murano. It is an expensive technique requiring great skill on the part of the glass maker, as the individual blown parts need to be identical in shape, or circumference, prior to being warm jointed together and shaped into the end form. Notable forms being the vases and lighting created by Thomas Stearns in the 1960s for Venini & C.

Lattimo

Refers to an opaque milky white glass produced in the mid 15th century to imitate porcelain, allowing direct competition with real porcelain pieces from China. At this time it was particularly useful for manufacturing objects decorated with multicolored enamels and was opacified using tin oxide or arsenic. The word originates from latte meaning milk.

The process fell into disuse only to be revived in the 1920s by the key glassworks of Barovier & C., Venini & C., and MVM Cappellin & C. The latter was the first to use it without the addition of other colours for a series of geometric vases exhibited at the 1927 International Exhibition of Decorative Arts in Monza. In the 1950s it was adopted by almost all the glass furnaces on the island, being used more diversely, including in the famous Commedia dell'Arte figures by Fulvio Bianconi for Venini & Co. In modern production the opaque effect is created by adding calcium and sodium fluorides to the molten glass mix in the form of fluorine compounds such as cryolite or fluorine spar, as well as zinc oxide and alumina.

Image: A mould blown lattimo vase attributed to Tomaso Buzzi or Carlo Scarpa for Venini & C. circa 1932 to 1935.

Massiccio

A technique in which large or heavy objects are produced without being blown because the molten glass is too heavy or dense to handle creatively. The glass is therefore shaped, moulded, or formed whilst the glass is hot and malleable. This process is often used for thick glass sculptures.

Millefiori (literally meaning a thousand flowers)

Is one of the oldest and most well known techniques still in use in Murano. It is used to describe small mosaic cross sections of glass. The process involves stretching and shaping regular arrangements of multicoloured rods of glass. Normally the colours are added and a shape is created before the molten glass is stretched into a long thin cane. The cane can then be cut to size for use as beads or placed on a gather of molten glass (pea) for inclusion into murrina paperweights or blown vases.

Murrina

One of the oldest techniques used in glass making dating back to Roman times and rediscovered in the 1800s. Thin sections of glass rod are placed together to form a pre-designed image before being fused together and then formed and moulded into shape or even blown. The rods are often designed to create a floral or geometric design.

Pasta Vitrea

Is based on the same principle as lattimo glass but takes it a stage further and as a result is one the most difficult glass making techniques to master. A coloured opaque glass is made by adding clear or coloured crystals to molten glass until it becomes similar in appearance to ceramic. Because of the complexity and mixed results this process was only been utilised by a handful of glass works at the outset of the 1900s, namely Venini & C. and MVM Cappellin & C.. Post war it was adopted more widely particularly when glass figures became fashionable in the 1950s. Only the American designer Thomas Stearns made large items entirely of vitreous paste for Venini & C.

Image: A red gather fused burst gold foil iridised pasta vitrea vase produced by Carlo Scarpa for MVM Cappellin & C. circa 1929.

Pennellate

A rare process developed by Carlo Scarpa for Venini & C in 1940. It sees the fusion of glass to the surface of a hot item that is still on the blower's pipe. Small balls of coloured glass are applied and then pulled over the surface of the blown object to leave a slight colour trace which is reminiscent of an artists brush or pennellata. This process is repeated until the entire surface of the object is covered. Often opaque glass in various shades of yellow, orange and red is used to obtain a slightly iridescent effect on the surface.

Image: A pennellate bowl by Carlo Scarpa circa 1942.

Perle a Lume Venetian Beads (also known as Lampwork or Wound beads)

These beads are often called wound beads because molten glass is wound around a mandrel to form the bead. Originally this was a ferrous mandrel covered with a mixture of silica and clay which gave the bead some room for contraction when it cooled and helped with removal of the bead from the mandrel. In 1935 copper mandrels were introduced into Murano by the Moretti glass works and soon became the standard tool for making lampwork beads. They proved more economical as the mandrels did not need to be coated and breakages were reduced as the copper mandrel was cut off just below the bead and the cut off section was placed in nitric acid which etched the copper from inside the bead. Today, bead makers in Venice and Murano still use both methods, using stainless steel with a bead release material for more delicate beads, or for beads with silver in them which tends to turn dark if it comes into contact with acid.

Pulegoso

A technique used to create an almost opaque glass through the inclusion of innumerable bubbles or puleghe in the glass. This process was invented by Napoleone Martinuzzi in the late 1920s, whilst he was artistic director at Venini & C. The bubbles are created by adding salts, generally sodium carbonate or bicarbonate directly into the molten glass. The salt breaks down due to the heat, which releases gasses in the form of carbon dioxide, which disperse within the glass forming bubbles as well as giving the glass an irregular surface texture.

This has remained an important process from the 1930s to the present day, with Vetreria Artistica, Barovier & C., Seguso Vetri d'Arte and others producing vases, figures and the famous blown and hand-shaped glass cactuses. Twenty five years later during the 1950s Dino Martens made the famous pittorici vases for the firm of Aureliano Toso, whilst Gae Aulenti was combining metal and pulegoso glass for Venini & C., in 1995.

Image: A pulegoso lamp produced by Ercole Barovier for Artistica Barovier circa 1930.

Sommerso (meaning submerged)

A technique using coloured threads or small artistic designs that are then submerged into various crucibles of colourless transparent molten glass to form a multi layered or multi hued effect. Once again Carlo Scarpa fro Venini & C. was at the forefront of this process from the mid 1930s. He made use of a layer of coloured glass along with gold leaf and frequently air bubbles which he would capture in a thick layer of transparent glass. This technique was quickly taken up by many of the other Muranese glass factories.

Image: Vintage Venetian baby blue sommerso lamp worked glass beads with blue opaque glass and aventurina, circa 1955.

Tessere

Created by fusing together pieces of glass of almost random shapes or sizes before blowing or working into a finished object.

Image: Barovier & Toso clear glass and fused ochre brown structured glass vase circa 1957.

Tessuto

A multi coloured glass invented by Carlo Scarpa for Venini and C. in the late 1930s. Based on the filigrana process, very thin rods of coloured glass are fused together to create an alternating pattern of stripes and then blown.

Image: Paolo Venini tessuto matte finish vase with mint green, brown and white stripes with horizontal texturing, circa 1985.

Zanfirico
A type of glass cane made by assembling a bundle of different coloured rods and heating them until soft. The bundle is then attached to two metal pontils or metal rods before being drawn out and elongated. During this process the bundle is twisted to produce a spiral pattern. This process was originally known as vetro a retorti, but was renamed in recognition of a Venetian dealer called Antonio Sanquirico, who in the 1830s encouraged the revival of this and other traditional techniques on Murano.



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