“Glass-blowing” is a method which has not changed a lot since its invention. In the simplest words it involves a glassmaker blowing inside the pipe in order to shape a glass object in the appropriate shape. What is significant in the look of products originating from Murano glassworks is that their magnificent appearance and colours are achieved due to special addition to the glass mixture. For example, adding gold or silver foil to the glass mixture will produce beautifully shimmering vases or bowls. When a glassmaker adds zinc, the glass will appear to be white; when adding cobalt, the product will have a sea deep blue tone; when mixing in manganese, the item will be violet. After the product is finished, a glassmaker places it in an oven called “tempera” in order to cool it down.
Below, you will find a short description of various techniques used by glassmakers on Murano Island.
The technique was discovered in Murano in the early 17th century and its application allows a coloured glass item to show the effect of colour change when tilted. The legend says that avventurina glass was invented by accident when cooper filling was spilled by a Murano glassmaker into the glass he was working on. The glass is achieved through adding metallic components such as cooper or chrome which are slowly crystallized out of the molten glass. It makes the glass object beautifully glittering. The word avventurina comes from the Italian word “ventura” which means fortune or chance.
Bubbles in the glass occur either because this is an intention of a glassmaker or as an accident due to improperly used technique or a glassmaker not having enough experience in this field. Hand-made products always have a few bubbles in it. Bullicate is a technique which is used with intention of creating a regular pattern of evenly spaced air bubbles. The bubbles can be larger or smaller. Single bubbles are pushed into molten glass with a spike which makes a sphere looks silvered when the glass cools. It was widely utilized in the 1950s.
The technique was invented in the 15th century on the Murano Island however soon after the formula for this kind of glass was lost for many years. The main characteristic of the calcedonio glass is visibility of polychromatic veins which run through the dark-coloured glass. As a result, by mixing various metal compounds in a certain fashion, the look imitating natural stones, such as chalcedony, agate or malachite is achieved. The usual metals used in this technique are silver and mineral oxides, such as copper, iron, or manganese, melted with opaline glass.
Cameo glass is a unique luxury form of glass art. It involves fusing two layers of different colour glass and later etching and carving the object to create a design. The most famous forms of cameo glass present white opaque glass figures and motifs on a dark coloured background. Some of the objects may also be carved in a manner to reveal portions of the underlying colours. This technique was first used by ancient Romans in 30BC, and was particularly popular among British artists in early 20th century.
Cristallo, invented in 1450 in Venice by a master of glass, Angelo Borovier, is famous for being first truly colorless glass, totally clear, without any yellow or greenish color originating from iron oxide impurities. It is achieved by bleaching glass mixture with help of manganese or other de-colorants.
Fenicio was used on glass even in the 200s AD, and at the end of the 17th century it was adopted by Murano glassmakers. It involves a glassworker to wrap the incandescent glass threads with a thin pontil and to comb the threads with a hooked tool when the object is still hot. After the threads are merged into a single piece of glass, the glassmaker achieves decoration which reminds festoons or feathers.
The filigrana technique was invented in the 1500s. Its final products are pieces which have an opaque white or coloured core. The technique involves using glass rods fused together, then blown and shaped by the glassmaker. There are three patterns which are produced when utilizing the filigrana technique. These are: mezza filigrana (single filament rods), reticello (diamond pattern where the threads cross and form a grid which is created as a result of twisting two halves of a glass piece in opposite directions during heating) and retortoli (two filaments twisted into a spiral shape and not crossing).
GHIACCIO (ICE GLASS)
Popular in the 16th to 18th century, the technique involves immersing still hot glass object in cold water. It leads to creation of a glass item which appears cracked on its surface, similar to crocked ice. After immersion in cold water, the crackles are covered with another layer of glass.
Incalmo glass was produced for the first time in the 16th century when Italian glassmakers looked for a technique which would allow them to make glass objects with two or three different coloured sections of glass looking as if it was one piece. Many different coloured glass pieces are fused together when the glass is still flexible to form a single piece.
LATTIMO (MILK GLASS)
Italian glassmakers have been using this technique since the 15th century. The main objective was to produce opaque white glass which would imitate popular that time fine china.
This is the ancient technique which used for the first time in Egypt between the 3rd and 1st century BC and is still utilized by Murano glassmakers. It involves using thin sections of glass rods which are fused together, blown and then formed to create shapes, often in floral or geometric designs.
Invented in 1930s in Murano, the Sommerso technique allows to create objects with a layered appearance where on coloured layer of glass is covered by another one of different colour. Such an effect is created by using layers of glass formed by dipping the glass object into molten glass of another colour.