Understanding the various Murano Glass manufacturing techniques
Since ancient times, glass has held a mesmerizing, almost magical fascination for people. Some of the techniques that go into the making of this magnificent glass are enumerated here.
Murano Glass has always been both functional and decorative. As the techniques of glass making have evolved, Murano Glass has become more and more beautiful along with being useful and valuable.
Murano glassmaking is an extremely complex process. Several glassmaking techniques have been developed over the centuries.
It includes countless particles of gold within its mass which are minute copper cyrstals with copper as its basic colouring agent. Metal flecks are embedded in clear glass to reflect light. Copper, metallic siliconand other metal oxides are added to create a shimmery, metallic look.
A diamond patterned decoration in relief which is obtained by blowing the glass into the appropriate bronze mould. The shape is then obtained freehand.
This is applied to very thick glass. It consists of overlaying several layers of air bubbles in a grid pattern within the vitreous wall. This mass is then pulled with the blowpipe which creates tiny depressions imprinted in a regular pattern on its surface. This process is repeated several times to reveal several layers of bubbles.
This is a type of glass with two thin superimposed layers. The inside layer may be opaque white to let the outer layer remain opaque.
Glass featuring polychromatic veins running through the dark-colored glass. This look is obtained by mixing various metal compounds in a certain fashion, to imitate the natural stones such as chalcedony, agate, and malachite. It was known and used in ancient Egypt, and then re-discovered in Murano in the fifteenth century.
This is obtained by wrapping a coloured vitreous thread in a spiral around the body of the blown piece, then near the glory-hole, it is combed with a hooked tool.
This technique is used to create pieces with an opaque white or colored glass core, using glass rods fused together, then blown and shaped by the artist.
A blow piece “a tessere” is obtained by using tesserae in various shapes cut from the surfaces of blown pieces in various colours. The slab fused in the heat is gathered with a blowpipe and shaped into a vessel.
In the first phases of hot-work, the glass-master rolls the flaming glass on the end of the blowpipe over thin leaves of gold or silver. As the glass is blown, the leaves reduce to fine pieces into gold or silver dust. This technique is generally used together with enamel painting.
The glassworker stretches a glass rod, differently coloured inside and outside. These rods are cut into same length and are laid parallel to each other on a metal surface covered with clay and are then inserted repeatedly into the furnace. The glassmaker then picks up the material with a blowpipe and shapes the object.
This is glass with a “craquele’” appearance, obtained by dipping the flaming glass into a bucket of water, heating it again and covering it by immersion with another vitreous layer.
This is a technique consisting in joining two blown cylinders. If the two equal cylinders are of different colours or decorated differently, a single blown piece is obtained with two zones of different colours or decorations. The process may be repeated more than once.
Iridescence is an effect where the light reflected from the surface of the glass decomposes into the colours of the rainbow. It is obtained by exposing the work in progress, on the end of the blow-pipe to the vapours produced by burning quick-melting salts of tin, titanium or other metals.
Opaque white glass produced for the first time in Murano in the fifteenth century, imitating the look of fine china. It was originally used for manufacturing objects decorated with multicolored enamels.
Macette – Spots
The “macette”, literally little spots, cover the surface in an irregular manner, when the blown piece on the end of the blow-pipe is rolled over the marver on which are strewn small shards of coloured glass (“granzioni”) which adhere to the surface. The shards may be left in relief or absorbed into the walls, by rolling, or dilated by blowing.
The basis of this technique is the use of glass canes (rods) which contain a single flower design visible only on the surface of cross sections of the cane. The object is then formed using the cross-sections of multiple such rods, which are melted together to cover the surface of the glass object. This technique was first used in Egypt between the third and the first century B.C.
A type of glass characterized by countless irregular air bubbles (pulighe) within the vitreous wall which deliberately obscure its transparency. It is obtained by pouring substances such as petrol into the pot which produce a boiling over of the glass in fusion.
The “reticello” is characterised by a fine netting of threads. The glassworker prepares clear rods with white or coloured threads inside wrapped in a spiral. On a slab he positions equal segments of this rod, parallel and adjacent. He then uses his blowpipe to shape them in a cylindrical form.
A decorative motif characterized by subtle ribs in relief, obtained by blowing the glass into a bronze mould. The mould determines the decorative motif but not the shape which is made freehand.
This technique requires a blown work in thick glass to be immersed in a pot containing transparent glass of a different color and of equal thickness overlaying thick transparent glass to obtain particular chromatic effects.