A glass blank is a piece of glass that requires additional decoration before it is considered finished. [1] Types of decoration include cutting, engraving, acid-etching, gilding, and enameling. Often the term blank is used in reference to an uncut piece of glass that will be cut or engraved. [2] "Blank" is used in the same way of pottery, especially porcelain, that was often decorated elsewhere, for example by hausmalers.
The glassmaking process can be divided into several stages, including: melting ingredients to make raw glass, remelting raw glass to make objects (sometimes adding decorations while the glass is still hot), and adding decorations to cooled glass objects. The last stage is often where blanks are involved. These are pieces of glass made with the intention of adding decoration to the cooled piece. [3] Blanks are sometimes made in the same factory or studio in which they are decorated, but blanks can also be made and sold by one company to another company that adds decoration.
In glass engraving plain wineglasses that were many years old are often used. A glass engraved in Utrecht to celebrate the birth of William V, Prince of Orange in 1748, showing an orange tree with a new shoot, uses an English wineglass made about 30 years earlier. [4]
Cased glass blanks and figured blanks are two types of blanks made with specific finishing decorations in mind. A cased glass blank is an object made with several layers of colors. When it is decorated (often by cutting or engraving) the lower layers of one or more different colors are revealed. [2] A popular example of pieces made using cased glass blanks are cameo glass objects.
Figured blanks are made when hot glass is blown into a mold. While the molded shape is considered part of the decoration, additional details are often added after the glass is cooled. [2]
Engraving is the practice of incising a design onto a hard, usually flat surface by cutting grooves into it with a burin. The result may be a decorated object in itself, as when silver, gold, steel, or glass are engraved, or may provide an intaglio printing plate, of copper or another metal, for printing images on paper as prints or illustrations; these images are also called "engravings". Engraving is one of the oldest and most important techniques in printmaking. Wood engraving is a form of relief printing and is not covered in this article.
Émile Gallé was a French artist and designer who worked in glass, and is considered to be one of the major innovators in the French Art Nouveau movement. He was noted for his designs of Art Nouveau glass art and Art Nouveau furniture, and was a founder of the École de Nancy or Nancy School, a movement of design in the city of Nancy, France.
Cameo is a method of carving an object such as an engraved gem, item of jewellery or vessel. It nearly always features a raised (positive) relief image; contrast with intaglio, which has a negative image. Originally, and still in discussing historical work, cameo only referred to works where the relief image was of a contrasting colour to the background; this was achieved by carefully carving a piece of material with a flat plane where two contrasting colours met, removing all the first colour except for the image to leave a contrasting background.
Glassblowing is a glassforming technique that involves inflating molten glass into a bubble with the aid of a blowpipe. A person who blows glass is called a glassblower, glassmith, or gaffer. A lampworker manipulates glass with the use of a torch on a smaller scale, such as in producing precision laboratory glassware out of borosilicate glass.
Art glass is a subset of glass art, this latter covering the whole range of art made from glass. Art glass normally refers only to pieces made since the mid-19th century, and typically to those purely made as sculpture or decorative art, with no main utilitarian function, such as serving as a drinking vessel, though of course stained glass keeps the weather out, and bowls may still be useful.
Laser engraving is the practice of using lasers to engrave an object. Laser marking, on the other hand, is a broader category of methods to leave marks on an object, which in some cases, also includes color change due to chemical/molecular alteration, charring, foaming, melting, ablation, and more. The technique does not involve the use of inks, nor does it involve tool bits which contact the engraving surface and wear out, giving it an advantage over alternative engraving or marking technologies where inks or bit heads have to be replaced regularly.
Lampworking is a type of glasswork in which a torch or lamp is used to melt the glass. Once in a molten state, the glass is formed by blowing and shaping with tools and hand movements. It is also known as flameworking or torchworking, as the modern practice no longer uses oil-fueled lamps. Although lack of a precise definition for lampworking makes it difficult to determine when this technique was first developed, the earliest verifiable lampworked glass is probably a collection of beads thought to date to the fifth century BC. Lampworking became widely practiced in Murano, Italy in the 14th century. As early as the 17th century, itinerant glassworkers demonstrated lampworking to the public. In the mid-19th century lampwork technique was extended to the production of paperweights, primarily in France, where it became a popular art form, still collected today. Lampworking differs from glassblowing in that glassblowing uses a furnace as the primary heat source, although torches are also used.
Mercury glass is glass that was blown double walled, then silvered between the layers with a liquid silvering solution, and sealed. Although mercury was originally used to provide the reflective coating for mirrors, elemental mercury was never used to create tableware. Silvered glass was free-blown, then silvered with a solution containing silver nitrate and grape sugar in solution, heated, then closed. Sealing methods include metal discs covered with a glass round or a cork inserted into the unpolished pontil scar. "Mercury" silvered glass was produced originally around 1840 until at least 1930 in Bohemia, Germany and was also manufactured in England from 1849 to 1855.
The term "opaline" refers to a number of different styles of glassware.
In glassblowing, cane refers to rods of glass with color; these rods can be simple, containing a single color, or they can be complex and contain strands of one or several colors in pattern. Caneworking refers to the process of making cane, and also to the use of pieces of cane, lengthwise, in the blowing process to add intricate, often spiral, patterns and stripes to vessels or other blown glass objects. Cane is also used to make murrine, thin discs cut from the cane in cross-section that are also added to blown or hot-worked objects. A particular form of murrine glasswork is millefiori, in which many murrine with a flower-like or star-shaped cross-section are included in a blown glass piece.
Glass production involves two main methods – the float glass process that produces sheet glass, and glassblowing that produces bottles and other containers. It has been done in a variety of ways during the history of glass.
Engraved glass is a type of decorated glass that involves shallowly engraving the surface of a glass object, either by holding it against a rotating wheel, or manipulating a "diamond point" in the style of an engraving burin. It is a subgroup of glass art, which refers to all artistic glass, much of it made by "hot" techniques such as moulding and blowing melting glass, and with other "cold" techniques such as glass etching which uses acidic, caustic, or abrasive substances to achieve artistic effects, and cut glass, which is cut with an abrasive wheel, but more deeply than in engraved glass, where the engraving normally only cuts deeply enough into the surface to leave a mark. Usually the engraved surface is left "frosted" so a difference is visible, while in cut glass the cut surface is polished to restore transparency. Some pieces may combine two or more techniques.
A glossary of terms used in glass art
Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting materials are usually metals or various time setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. Heavy equipment like machine tool beds, ships' propellers, etc. can be cast easily in the required size, rather than fabricating by joining several small pieces.
Cameo glass is a luxury form of glass art produced by cameo glass engraving or etching and carving through fused layers of differently colored glass to produce designs, usually with white opaque glass figures and motifs on a dark-colored background. The technique is first seen in ancient Roman art of about 30 BC, where it was an alternative to the more luxurious engraved gem vessels in cameo style that used naturally layered semi-precious gemstones such as onyx and agate. Glass allowed consistent and predictable colored layers, even for round objects.
China painting, or porcelain painting, is the decoration of glazed porcelain objects such as plates, bowls, vases or statues. The body of the object may be hard-paste porcelain, developed in China in the 7th or 8th century, or soft-paste porcelain, developed in 18th-century Europe. The broader term ceramic painting includes painted decoration on lead-glazed earthenware such as creamware or tin-glazed pottery such as maiolica or faience.
Enamelled glass or painted glass is glass which has been decorated with vitreous enamel and then fired to fuse the glasses. It can produce brilliant and long-lasting colours, and be translucent or opaque. Unlike most methods of decorating glass, it allows painting using several colours, and along with glass engraving, has historically been the main technique used to create the full range of image types on glass.
Art Nouveau glass is fine glass in the Art Nouveau style. Typically the forms are undulating, sinuous and colorful art, usually inspired by natural forms. Pieces are generally larger than drinking glasses, and decorative rather than practical, other than for use as vases and lighting fittings; there is little tableware. Prominently makers, from the 1890s onwards, are in France René Lalique, Emile Gallé and the Daum brothers, the American Louis Comfort Tiffany, Christopher Dresser in Scotland and England, and Friedrich Zitzman, Karl Koepping and Max Ritter von Spaun in Germany. Art Nouveau glass included decorative objects, vases, lamps, and stained glass windows. It was usually made by hand, and was usually colored with metal oxides while in a molten state in a furnace.
Cut glass or cut-glass is a technique and a style of decorating glass. For some time the style has often been produced by other techniques such as the use of moulding, but the original technique of cutting glass on an abrasive wheel is still used in luxury products. On glassware vessels, the style typically consists of furrowed faces at angles to each other in complicated patterns, while for lighting fixtures, the style consists of flat or curved facets on small hanging pieces, often all over. Historically, cut glass was shaped using grinding or drilling techniques applied as a secondary stage to a piece of glass made by conventional processes such as glassblowing. Today, the glass is often mostly or entirely shaped in the initial process by using a mould, or imitated in clear plastic. Traditional hand-cutting continues, but gives a much more expensive product.
Susa is one of the most important archaeological sites in Iran, on the border between the Mesopotamian world and the Persian world. Inhabited since very ancient times, it remained occupied until the middle of the 15th century. Excavations carried out by French teams, allowed the discovery of many objects, including a large production of ceramics dating from the Islamic period, currently kept for a large part at the Louvre.