T. (talcum - turpentine)

Talcum  -  1. An obsolete Latin term for talc. 2. A perfumed dusting powder, usually made with powdered talc.
This is mentioned as one of the polishes for stucco marble introduced in the twentieth century (along with tin ashes, rottenstone polishing-red, polishing lime, and sorrel salt).
Synonyms: talc
Museum of Fine Arts, Boston (2000); Wittenburg (1999)

Tallow - A hard fat obtained from animals, especially beef and sheep. Tallow is separated by moisture and fibrous tissue by melting and cooling. It primarily contains fatty acids: oleic (37-43%), palmitic (24-32%), stearic (20-25%), myristic (3-6%), linoleic (2-3%). Oleo stock refers to the highest grade of beef tallow. 
Synonyms: oleo stock
Museum of Fine Arts, Boston (2000)

Tar - A viscous, black crude oil obtained from the distillation of peat, wood, coal or other organic substances, chemically a  mixture of hydrocarbons with resins. Some tars, such as those obtained from pine or beech wood, have been mixed with linseed oil to form a dark brown glaze (White, 1986).
Synonyms: coal tar; mineral tar; pine tar; wood tar; birch bark tar; creosote
Museum of Fine Arts, Boston (2000);  English Heritage (2000)

Tempera - A water thinned paint that dries to a water resistant film. Egg tempera is an aqueous emulsion paint with an egg yolk or whole egg binder that originated in medieval Europe. These paints dry to a semi-matt appearance by the evaporation of water and the coagulation of the egg protein. After about 1400 CE, variations of tempera were made with egg/oil, gum/oil, glue/oil and other emulsions as artists began to experiment with drying oils. As linseed oil paints became popular at the end of the 16th century, tempera died out. It enjoyed a revival near the end of the 19th century when Cennino's treatise was published. Other water thinned paints that dry to form a water soluble film (e.g., distemper, gouache, poster paint and watercolours) are sometimes incorrectly called tempera paints.
Synonyms: egg tempera; glue tempera; gum tempera; oil tempera
Museum of Fine Arts, Boston (2000)

Terra-cotta - A moulded fired clay product, used as a substitute material, very popular in the late 19th  and early 20th  centuries. It simulated the appearance of intricately carved stonework, which was expensive and time-consuming to produce. Terra cotta could be glazed to imitate a variety of natural stones, from brownstones to limestones, or could be coloured for a polychrome effect.
Park (1988)

Thickening agent - Any hydrophilic material that increases the viscosity of a liquid. Thickening agents are used in adhesives and paints. The main types of thickeners are  (based on Lewis 1993):  1. Natural products: starch, gum, casein, gelatin, agar, etc. 2. Synthetic cellulose derivatives: carboxymethyl cellulose, etc. 3. Polymers: polyvinyl alcohol; polyacrylate. 4. Inorganics: clay, bentonite, silicates, colloidal silica.
Synonyms: thickener; rheology modifier
Museum of Fine Arts, Boston (2000)

Tin ashes - stannic oxide SnO or SnO₂ - xH₂O. White powder that is often incorrectly called tin oxide. Stannic oxide, or
tin dioxide, occurs in nature as the mineral cassiterite. It is used as an abrasive. This is mentioned as one of the polishes for stucco marble introduced in the twentieth century (along with rotten stone, polishing-red, polishing lime, sorrel salt and talcum). 
Synonyms: stannic anhydride; tin peroxide; tin dioxide; tin oxide (sp); stannic acid; putty powder; putty; jewellerís putty; white tin oxide; flowers of tin; polishing powder; tin ash
Museum of Fine Arts, Boston (2000); Wittenburg (1999)

Titanium dioxide  TiO₂ - A dense, white, opaque powder often used as a pigment. Titanium dioxide occurs naturally in three crystalline forms: anatase, rutile and brookite. It is a very stable compound with a high refractive index. Titanium white pigment was prepared from ground rutile as early as 1870. Synthetic titanium dioxide was first prepared in 1906, was manufactured commercially in Norway and the United States in 1916 and sold under the name of Titanox. It contained 25% titanium dioxide co-precipitated with 75% calcium or barium sulphate. Both pure titanium and barium base titanium pigments have a very fine texture. Prior to 1938, only anatase was produced. However, white paints with anatase were subject to chalking and yellowing, so manufacturing shifted to the use of rutile in 1938 and rutile white pigments were first commercially produced in 1940. Currently, titanium pigments are usually sold as admixtures with zinc oxide. In addition to paints, titanium dioxide is used as an abrasive.
Synonyms: titanium white; rutile; anatase; brookite; Titanox; titania; Pigment White 6; CI 77891; titanic anhydride; titanic acid anhydride; titanic oxide; Unitane; titania; oxyde de titane (Fr.); Titandioxid (Ger.); bianco di titanio  (It.); dióxido de titanio (Sp.); titandioksid (Nor.)
Museum of Fine Arts, Boston (2000)

Titanium white - A durable white paint pigment used in the 20th century. Titanium white is composed of titanium dioxide. It is a very stable compound with a high refractive index. Titanium white pigment was prepared from ground rutile as early as 1870. Synthetic titanium dioxide was first prepared in 1906, was manufactured commercially in Norway and the United States in 1916 and sold under the name of Titanox. It contained 25% titanium dioxide co-precipitated with 75% calcium or barium sulphate. Both pure titanium and barium base titanium pigments have a very fine texture. Prior to 1938, only anatase was produced. However, white paints with anatase were subject to chalking and yellowing, so manufacturing shifted to the use of rutile in 1938 and rutile white pigments were first commercially produced in 1940. Currently, titanium pigments are usually sold as admixtures with zinc oxide. 
Synonyms: Titanox; titanium dioxide
Museum of Fine Arts, Boston (2000)

Tobermorite  - (1) A mineral found in northern Ireland and elsewhere, having the formula 5CaO.6SiO₂.5H₂O. (2) Ca:4HO, the artificial product tobermorite, G,  of Brunauer, a hydrated calcium silicate having CaO/SiO ratio in the range  1.39 to 1.75. It forms minute layered crystals that constitute the principal cementing medium in Portland cement concrete, being also responsible for important engineering properties such as strength, shrinkage, permeability and resistance to the stresses of freezing and thawing. The mineral has 5 mols of  lime to 6 mols of silica, and usually occurs in plate-like crystals.
Chong (1977);  RS Means Building Glossary (undated)

Tobermorite gel -  The binder of concrete cured moist or in atmospheric-pressure steam. A lime-rich gel-like solid containing 1.5 to 2.0 mols of lime per mol of silica.  RS Means Building Glossary (undated)

Trass -  A light coloured volcanic ash used in hydraulic cement. Trass is similar to pozzolana, but is found in Germany, France and the Netherlands.
Museum of Fine Arts, Boston (2000)

Travertine - A light-coloured, porous rock composed of calcium carbonate. Travertine is formed from multilayered calcium carbonate deposits usually near hot and cold spring waters, streams or lakes. Plant residues are often layered with the calcite deposits resulting in large elongated, often interconnected pores in the stone. Very porous, spongy travertine is called tufa. Travertine polishes to a matte finish. It is used as an interior and exterior building material. Thick deposit of travertine occur near Tivoli, Italy. 
Synonyms: tufa limestone; false marble; travertin; Mexican onyx; Egyptian alabaster
Museum of Fine Arts, Boston (2000)

Tripoli -  A fine, naturally occurring, lightweight silica. Tripoli is a sedimentary stone composed of diatoms and finely weathered chert. It is derived from schistose rocks. It was originally obtained from northern Africa, but is now quarried in the USA.  Tripoli is used as an abrasive, as a filtering medium and as a filler in paints.
Synonyms: tripolite; tripoli powder; diatomaceous earth; soft silica 
Museum of Fine Arts, Boston (2000); Trench (2000)

Tufa - A porous, calcareous mineral formed by hot springs, dry lakes or ground water deposits. It can be coloured yellow or red, due to the presence of iron oxides. Tufa is a microcrystalline type of limestone that has been used occasionally since ancient times for sculptures (Mayer 1969). It is lightweight and has been used to fill the spaces between the ribs of vaulted ceilings. It has also been used as a building stone, for example in Verona. 
Synonyms: calc-tufa; calc-tuff; calcareous tufa; tufa limestone
Museum of Fine Arts, Boston (2000); Mayer (1969); Trench (2000)

Tufaceous limestone  (Travertine, Tufa) - Very light, depositional limestone formed by the precipitation of calcium carbonate rich water (Tufa). The more dense and compact form, Travertine, is formed in a similar way. 
English Heritage (2000)

Tuff  - An igneous rock composed of fine-grained volcanic ash which has become solidified over time. It is generally white or grey and is soft enough to be easily worked. Tuff has been used as a building stone in Italy and Germany, where it is known locally as trass. Tuff is also added to lime to obtain a hydraulic set.
Trench (2000)

Tuffaceous limestone - A sedimentary limestone that contains up to 50 percent volcanic tuff (ash and cinders). Tuffaceous limestone is often light or dark green with some grey and blue varieties. It can have predominant grains of calcite with small amounts of iron oxide, quartz, plagioclase and glass shards. 
Synonyms: Tuff
Museum of Fine Arts, Boston (2000)

Turpentine (oil) -  A volatile, flammable liquid used for thinning oil paints. Turpentine is obtained as the steam distillate from gum turpentine. It is a mixture of cyclic monoterpene hydrocarbons, such as pinene. Turpentine is primarily used as a solvent for paints and varnishes and as a cleaner for paint brushes. It is also a good solvent for many natural resins, waxes, oils, plastics and rubber. The best quality turpentine is fresh, clear and thin. Turpentine thickens and yellows with age; moisture can cause cloudiness in varnishes. Three major grades of turpentine are: 
- Pure Gum Spirits of Turpentine (double distilled, rectified) is pure, and without water. This is the grade of turpentine used by artists. - Wood turpentine is made from ground wood. - Sulphate turpentine is obtained as a by-product of the paper pulping industry. - The chief varieties of turpentine are: - common turpentine (Pinus abies, Pinus sylvestis, etc.), 
- Venice turpentine (Larix Europea),  - Bordeaux turpentine (Pinus maritime), - Strasbourg turpentine (Abies picea), - China turpentine (Pistacia lentiscus), - Canadian turpentine (Abies balsamisfera), - Chian turpentine (Pistacia terebinthus), and 
- American turpentine (Pinus australix, Pinus taeda). 
It is listed among the substances used for coating the surface of stucco marble in the twentieth century.
 Synonyms: spirits of turpentine; turpentine; oil of turpentine; turps; huile de terebenthine (Fr.); Terpentinol (Ger.); gum spirits; wood turpentine; gum turpentine
 Museum of Fine Arts, Boston (2000); Wittenburg (1999)
 
 

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