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agerino = of an aquamarine color.
albol = lidless rectangular shaped wooden chest used to mix vitrifiable matters.
ancinello = hook for hanging utensils, such as blowing pipes or punties, generally hinged to the anzipetto.
anzipetto = refractory plate placed sideways to the furnace mouth, to the left of the worker and at chest height, to protect the glazier from the heat.
ara = reheating chamber, area of the furnace over the melting area, used for reheating and gradually cooling the glassware as soon as it is ready.
asio = refractory stone plate placed in front of the furnace mouth used as a support base.
barilla = sodium ash.
bocca = furnace opening, may it be for melting (calchera) or manufacturing.
bolo = glass paste that is collected from the melting pot with the blowing pipe once it is ready to be blown.
borsella = spring or pliers metal tool, of various shapes and measures, used by master blowers to mold the incandescent glass paste into the desired shape, or to puncture the glass paste to be placed on the pipe.
bronzin = iron or stonework plate with a flat and smooth surface on which glass taken from the melting pot is pressed and rolled in order to give it a cylindrical shape (this operation is also called marmorizar) before blowing it or putting it on the pipe.
calchera = reverb furnace used for the first fusion of the siliceous mixture, which is the vitrifiable matter, and the flux, which is soda, to obtain the fritta or for the calcination of some raw materials.
canna da soffio = long iron pipe, with a slightly conical shape on one end, used for blowing glass freehand or with a mold.
cavar in acqua = procedure used during the fusion of raw materials; it consists in taking the molten glass from the melting pot and placing it in water. It is then put back into the oven, alone or with other complementary raw materials.
coletto = small blown glass mass applied to a glass object.
conzaura = long iron utensil with compressed and whittled glass on one end. It is attached to the glass mass on the opposite side of where the pontello is placed, in order to be able to shape it with the blowing pipe.
ferro buso (or da buffar) = pipe for blowing glass.
forma = mold for blowing glass or pressing a decorative pattern.
fornasa = furnace; this term indicates both the furnaces and the area where they are found.
fritta = glass mass obtained calcining the mixture of the
two main components of glass: siliceous matter and the flux.
manganese = manganese dioxide, used in small quantities for discoloring the mixture for cristallino glass, in higher quantities to obtain different colors.
marmorizar = operation consisting in rolling the glass mass taken with the blowing pipe from the melting pot on the bronzin, in order to give it a cylindrical shape and let it cool slightly before blowing it.
paela = pan, melting pot in refractory material in which the vitrifiable matter to be inserted into the furnace is poured.
partia = lot, dosing of raw materials for the composition of a specific type of glass, generally according to a specific “recipe”.
pontelo = iron rod used during the processing of the incandescent paste to attach the glass mass to the opposite side of the blowing pipe.
resedello = filigree decoration, with net-like designs.
reffudi = rubbish.
refrescadora = container filled with fresh water.
retortoli = filigree decoration, with interwoven designs.
scagno = stall where the master sits to carry out some of the hot works of glass.
sculier = spoon.
soda = impure sodium carbonate, used as flux to lower the melting temperature of glass.
soffiadi = blown glassware.
speo = spit, long and thin iron rod, used to take small quantities of glass from the melting pot. These are usually needed for ornamental finishes.
tagianti = scissors used during hot working to eliminate glass in excess.
tolella = paddle that protects the master’s hands from the heat of the glass paste.
traghetar = to carry the melted glass paste from a melting pot of a furnace to a washbowl of water, or simply to carry the incandescent paste from one melting pot to another.
Some traditional types of glass and processing techniques
Aventurine in a brownish or reddish glass paste that presents bright golden spots (from which the name stellaria), scattered within its semi-opaque mass; these spots are laminated crystalline lenses of metal copper which remain suspended during the cooling phase. The term aventurine derives from the difficulty of foreseeing the good outcome of this paste, the production of which requires special care in checking the melting temperature. It was invented in Murano in the 17th century.
Chalcedony is a glass paste imitating the mineral by the same name. It was invented in Murano around the year 1450. It is made mixing glass debris of white opal, colored opal and crystal. At the end of the melting phase, a mix of coloring compounds such as silver nitrate, cobalt oxide, potassium dichromate and others is repeatedly added; these are then dispersed by mixing the melted paste again.
Melting-free heat coloring
This type of coloring is obtained by adding, to the still incandescent glass mass, substances which do not melt or do not have the time to melt, or glass fragments of a jarring color respect to the base one.
Intended as crystal or crystalline glass, or colorless glass paste, the typical Venetian one has been obtained, since the 15th century, from a mix of siliceous sands and soda ashes, with the adding of manganese dioxide as a decoloring agent. It is a pure type of glass, similar to quartz.
It is a decoration with very thin threads of opaque white glass, lattimo, or more rarely of colored glass, placed inside the thin wall of blown glass; the design can be with simple lines (a fili), helical weaving (a retortoli), or a network (a resedello or reticello). It was created in Murano in the 16th century.
Metal leaf (gold or silver)
This type of decoration, already attested in hellenistic and Roman times, became very common in Venice in the 15th century. It is made by rolling incandescent glass still attached to the blowing pipe on thin sheets of gold or silver. By blowing, the sheets pulverize. The metal plate can be applied on the cooled object as well, and some parts can be removed to form decoration patterns. Reheating, finally, solders the decoration.
Also called a glazo, it is a glass paste with a surface similar to ice, i.e. steamed, crazed and with many crackings on the surface; the effect is obtained by submitting the glass paste to sudden changes of temperature. Also this type of glass was invented in Murano in the 16th century.
Iridescence is an effect for which the reflected light decomposes into the colors of the rainbow. It is obtained by submitting the object under manufacture, still attached to the pipe or the punty, to the steam produced by burning lowmelting salts of tin, titanium or other metals. Thus, a very thin film of the corresponding metal oxide deposits on the surface. Light reflects through the metallic film creating colors that vary depending on the thickness of the films
Lattimo is a glass paste of an opaque white color, obtained by adding led andtin or led and arsenic. Often used for filigre decorations, it was invented in Murano around 1450 in order to imitate the porcelain which arrived to Venice from the Orient.
Opal is a white opalescent glass obtained with led arsenate crystals which, in addition to making it opaque, give the glass blueish reflections when the glass is observed in reflected light, brownish-reddish when observed in direct light. It was invented in Murano in the late 17th century.
The so called Rigadin is a decorative pattern characterized by thin embossed ribs obtained by blowing inside a bronze mold. This way, the mold determines the new decorative pattern, but not its shape, which is then handcrafted.
This antique technique, certified already around the mid 1st century b.C., revolutionized glass production. It was invented in the Siryan- Palestinian area and began to spread from the mid 1st century A.D. Mold glass blowing Mold glass blowing was adopted in the 1st century A.D. in the Roman Empire glasshouses, probably the ones of the Eastern coast of the Mediterranean. There are two main types of molds: the monoblock mold, which allows to print an embossed decoration on the glass surface, leaving the glassmaker the taskof shaping it; and the two, or more, hinged molds, which allow to print not only decoration patterns, but also a predetermined shape on the glass.
This type of glass is composed by two very thin overlapping layers. The internal layer may be, for example, opaque white; the external one, instead, colored or transparent. The external layer will appear opaque as well. This technique was widely used in Venetian artistic glass in the 19th century.