Glassblowing

Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a blowpipe (or blow tube).

The process of free-blowing involves the blowing of short puffs of air into a molten portion of glass called a "gather" which has been spooled at one end of the blowpipe.

The result proved that short clay blowpipes of about 30–60 cm (12–24 in) facilitate free-blowing because they are simple to handle and to manipulate and can be re-used several times.

[7] Skilled workers are capable of shaping almost any vessel forms by rotating the pipe, swinging it and controlling the temperature of the piece while they blow.

The former allows the finished glass object to be removed in one movement by pulling it upwards from the single-piece mold and is largely employed to produce tableware and utilitarian vessels for storage and transportation.

The Roman leaf beaker which is now on display in the J. Paul Getty Museum was blown in a three-part mold decorated with the foliage relief frieze of four vertical plants.

The final furnace is called the "lehr" or "annealer", and is used to slowly cool the glass, over a period of a few hours to a few days, depending on the size of the pieces.

Then, the molten glass is attached to a stainless steel or iron rod called a "punty" for shaping and transferring the hollow piece from the blowpipe to provide an opening and to finalize the top.

Blocks are ladle-like tools made from water-soaked fruitwood, and are used similarly to the marver to shape and cool a piece in the early steps of creation.

In similar fashion, pads of water-soaked newspaper (roughly 15 cm (6 in) square, 1.3 to 2.5 centimetres (0.5 to 1 in) thick), held in the bare hand, can be used to shape the piece.

These pieces of color can be arranged in a pattern on a flat surface, and then "picked up" by rolling a bubble of molten glass over them.

One of the most exacting and complicated caneworking techniques is "reticello", which involves creating two bubbles from cane, each twisted in a different direction and then combining them and blowing out the final form.

Lampworkers, usually but not necessarily work on a much smaller scale, historically using alcohol lamps and breath- or bellows-driven air to create a hot flame at a workbench to manipulate preformed glass rods and tubes.

The craft, which was raised to an art form in the late 1960s by Hans Godo Frabel (later followed by lampwork artists such as Milon Townsend and Robert Mickelson), is still practiced today.

The ancient Romans copied the technique consisting of blowing air into molten glass with a blowpipe making it into a bubble.

[10][26] On the eastern borders of the Empire, the first large glass workshops were set up by the Phoenicians in the birthplace of glassblowing in contemporary Lebanon and Israel as well as in the neighbouring province of Cyprus.

Mold-blown glass vessels manufactured by the workshops of Ennion and other contemporary glassworkers such as Jason, Nikon, Aristeas, and Meges, constitutes some of the earliest evidence of glassblowing found in the eastern territories.

[7][28] The Roman hegemony over the Mediterranean areas resulted in the substitution of glassblowing for earlier Hellenistic casting, core-forming and mosaic fusion techniques.

[1] The earliest evidence of blowing in Hellenistic work consists of small blown bottles for perfume and oil retrieved from the glass workshops on the Greek island of Samothrace and at Corinth in mainland Greece which were dated to the 1st century AD.

[11] Later, the Phoenician glassworkers exploited their glassblowing techniques and set up their workshops in the western territories of the Roman Empire, first in Italy by the middle of the 1st century AD.

[25][30][31] One of the most prolific glassblowing centers of the Roman period was established in Cologne on the river Rhine in Germany by the late 1st century BC.

[11][30] The glass blowing tradition was carried on in Europe from the medieval period through the Middle Ages to the Renaissance in the demise of the Roman Empire in the 5th century AD.

[33][34] Blown glass objects, such as the drinking vessels that imitated the shape of the animal horn were produced in the Rhine and Meuse valleys, as well as in Belgium.

[35][36] The technique of glassblowing, coupled with the cylinder and crown methods, was used to manufacture sheet or flat glass for window panes in the late 17th century.

[41] The subject of mystery novelist Donna Leon's Through a Glass, Darkly is the investigation of a crime in a Venetian glassworks on the island of Murano.