Mercury glass (or silvered 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 (now the Czech Republic), Germany and was also manufactured in England from 1849 to 1855.
Edward Varnish and Frederick Hale Thomson patented the technique for silvering glass vessels in 1849. The double walled blanks were furnished by James Powell. The English examples were often cased with a layer of colored glass in jewel tones of ruby red, cobalt blue, amethyst purple and emerald green then cut to silver as illustrated in the photograph. English signatures on silvered glass include E. Varnish & Co. London, Thomson, London and Thomas Lund.
Blown glass is made utilizing a long metal blowpipe by the glass blower who shapes and heats the object. The piece is attached to a long, flat-topped iron called a pontil to the end of the piece, with a small piece of molten glass, and the blowpipe is now cracked off. The workman completes the object and then, the pontil rod or "punty" is cracked off leaving the familiar rough pontil scar.
Companies in the United States, including the Boston and Sandwich Glass Company, New England Glass Company, Union Glass Co., and the Boston Silver Glass Company, made silvered glass from about 1852–1880. The New England Glass Company displayed a variety of silvered glass articles including copper wheel engraved goblets, vases and other tableware at the 1853 New Crystal Palace Exhibition.
Silvered mercury glass from Bohemia was also decorated with a variety of techniques including painting, enameling, etching, and surface engraving.
Silvered "mercury" glass is considered one of the first true "art glass" types, that is, glass that was made for display and for its inherent artistic value rather than for utilitarian use.
Authentic antique silvered glass pieces are still available in a wide range of decorative items and usually sold as mercury glass.
There are many reproductions currently marketed as "mercury glass", in table form, ornaments and other objects. New "mercury glass" can be distinguished from antique silvered glass in several ways, including lack of a double wall, and solid bottoms that are different from true antique silvered glass. [1] [2]
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.
Collodion is a flammable, syrupy solution of nitrocellulose in ether and alcohol. There are two basic types: flexible and non-flexible. The flexible type is often used as a surgical dressing or to hold dressings in place. When painted on the skin, collodion dries to form a flexible nitrocellulose film. While it is initially colorless, it discolors over time. Non-flexible collodion is often used in theatrical make-up. Collodion was also the basis of most wet-plate photography until it was superseded by modern gelatin emulsions.
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.
Gilding is a decorative technique for applying a very thin coating of gold over solid surfaces such as metal, wood, porcelain, or stone. A gilded object is also described as "gilt". Where metal is gilded, the metal below was traditionally silver in the West, to make silver-gilt objects, but gilt-bronze is commonly used in China, and also called ormolu if it is Western. Methods of gilding include hand application and gluing, typically of gold leaf, chemical gilding, and electroplating, the last also called gold plating. Parcel-gilt objects are only gilded over part of their surfaces. This may mean that all of the inside, and none of the outside, of a chalice or similar vessel is gilded, or that patterns or images are made up by using a combination of gilt and ungilted areas.
Uranium glass is glass which has had uranium, usually in oxide diuranate form, added to a glass mix before melting for colouration. The proportion usually varies from trace levels to about 2% uranium by weight, although some 20th-century pieces were made with up to 25% uranium.
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 BCE. 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.
Opaline glass is a style of antique glassware that was produced in Europe, particularly 19th-century France. It was originally made by adding materials such as bone ash to lead-crystal, creating a semi-opaque glass with reddish opalescence.
Blenko Glass Company, located in Milton, West Virginia, makes hand-blown glass.
Distressing in the decorative arts is the activity of making a piece of furniture or object appear aged and older, giving it a "weathered look". There are many methods to produce an appearance of age and wear. Distressing is viewed as a refinishing technique although it is the opposite of finishing in a traditional sense. In distressing, the object's finish is intentionally destroyed or manipulated to look less than perfect, such as with sandpaper or paint stripper. For example, the artisan often removes some but not all of the paint, leaving proof of several layers of paint speckled over wood grain underneath. This becomes the "finished" piece.
The firm of James Powell and Sons, also known as Whitefriars Glass, were London-based English glassmakers, leadlighters and stained-glass window manufacturers. As Whitefriars Glass, the company existed from the 17th century, but became well known as a result of the 19th-century Gothic Revival and the demand for stained glass windows.
A glossary of terms used in glass art
Privy digging is the process of locating and investigating the contents of defunct outhouse vaults. The purpose of privy digging is the salvage of antique bottles and everyday household artifacts from the past. Privy digging is a form of historical digging and is often conducted on private residential properties. Construction sites and major developments around older areas of towns and cities are also likely places to look for evidence of privies.
Early American molded glass refers to glass functional and decorative objects, such as bottles and dishware, that were manufactured in the United States in the 19th century. The objects were produced by blowing molten glass into a mold, thereby causing the glass to assume the shape and pattern design of the mold. When a plunger rather than blowing is used, as became usual later, the glass is technically called pressed glass. Common blown molded tableware items bearing designs include salt dishes, sugar bowls, creamers, celery stands, decanters, and drinking glasses.
Libbey, Inc., is a glass production company headquartered in Toledo, Ohio. It was originally founded in 1818 in Cambridge, Massachusetts, as the New England Glass Company, before relocating to Ohio in 1888 and renaming to Libbey Glass Co. After it was purchased in 1935, it operated as part of the Libbey-Owens-Ford company and as a division of the Owens-Illinois glass company until 1993, when it was separated back into an independent company.
Conservation and restoration of movable cultural property is a term used to denote the conservation of movable cultural property items in libraries, archives, museums and private collections. Conservation encompasses all the actions taken toward the long-term preservation of cultural heritage. Activities include examination, documentation, treatment, and preventive care, which is supported by research and education. Object conservation is specifically the actions taken to preserve and restore cultural objects. The objects span a wide range of materials from a variety of cultures, time periods, and functions. Object conservation can be applied to both art objects and artifacts. Conservation practice aims to prevent damage from occurring, a process known as 'preventive conservation'. The purpose of preventive conservation is to maintain, and where possible enhance, the condition of an object, as well as managing deterioration risks, such as handling and environmental conditions. Historically, object conservation was focused on the category of fine arts but now many different types of objects are conserved. Each type of object material, typically denoted by organic or inorganic then the specific medium, requires a specialized professional conservator and often requires collaborative work between museum staff, scientists, and conservators.
Pairpoint Glass Company is an American glass manufacturer based in Sagamore, Massachusetts. It is currently the oldest operating glass company in the United States.
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.
The conservation and restoration of photographic plates is the practice of caring for and maintaining photographic plates to preserve their materials and content. The practice includes the measures that can be taken by conservators, curators, collection managers, and other professionals to conserve the material unique to photographic plate processes. This practice includes understanding the composition and agents of deterioration of photographic plates, as well as the preventive, and interventive conservational measures that can be taken to increase a photographic image's longevity.
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.