I, J, K. (indian red - kieselguhr)

Indian red - A red iron oxide powder used as an artists pigment. Indian red is a brick red colour. It was originally the name for a red earth pigment imported from the Persian Gulf and India. In the early 18th century, a synthetic Indian red composed of pure ferric oxide was made from steel mill wastes. It is a dense, opaque, permanent pigment. It is listed among the pigments used for colouring stucco marble in the nineteenth and twentieth century.
Synonyms: India red; Venetian red; red iron oxide; Pigment Red 101; colcothar; Pompeian red; light red; roofers red; iron saffron
Wittenburg (1999); Museum of Fine Arts, Boston (2000)

Indigo C₁₆H₁₀N₂O₂  -  A natural dark blue dye obtained from Indigofera tinctoria plants native to India, Java and other tropical areas. The use of indigo was first mentioned in Indian manuscripts in the 4th century BCE. It was exported to Europe in Roman times but did not become plentiful until sea routes opened up in the 17th century. The natural material is collected as a precipitate from a fermented solution of the plant. The colouring component, indigotin, is extracted as a colourless glycoside, but turns blue with oxidation. Synthetic indigo was first produced in 1880 by Adolf von Baeyer and became commercially available in 1897. Made from anthranilic acid, the synthetic colorant is chemically identical to natural indigo and has almost entirely replaced the natural dyestuff. Indigo is a fine, intense powder which may be used directly as a pigment in oil, tempera or watercolour media. It is listed among the pigments and dyes used for colouring stucco marble in the seventeenth and eighteenth century.
Synonyms: indigotin; India blue; intense blue; rock indigo; stone blue; indigo carmine; intense blue; indico; indicoe; indicum (Pliny); indego; nil; indigo (Fr.); Indigo (Ger.); anil (Sp.); indaco (It.); aneel; anile; ai (Jap.); blue ynde; blue inde; anneil; Natural Blue 1; CI 75780 (natural); Vat Blue 1; CI 73000 (synthetic); Pigment Blue 66
Trench (2000); Wittenburg (1999); Museum of Fine Arts, Boston (2000)

Iron oxide red -  Iron oxides, in hydrated and anhydrous forms, produce a wide variety of red shades ranging from light, bright red to a deep purplish red. They can be natural, earth pigments (hematite, Indian red, Venetian red) or synthetically prepared pigments (light red). All iron oxide reds are stable, permanent pigments with good tinting strength. Iron oxides generally provide the colour in ochres and siennas. It is listed among the pigments used for colouring stucco marble in the nineteenth and twentieth century.  It is also mentioned among the polishing-red (one of the components?) used as polish.
Synonyms: red iron oxide; red ochre; red ochre; haematite; hematite; Indian red; caput mortum; rouge; Persian red; Tuscan red, Pompeian red; light red; Venetian red; terra Pozzuoli; English red; pozzuolana, terra di Pozzuoli
Wittenburg (1999); Museum of Fine Arts, Boston (2000)

Iron vitriol - The term vitriol, now obsolete, was formerly applied to a number of metal sulphates because of their glassy appearance. In the twentieth century, coloration of stucco marble was obtained by chemical reaction involving copper vitriol, iron vitriol, gypsum and alum with lime.  See also : vitriol.
Hampel and Hawley (1982); Wittenburg (1999)

Ivory black - An impure black carbon pigment originally prepared from charred ivory or horns. Ivory black is a fine-grained, intense black pigment. Current formulations of ivory black usually contain a fine grade of animal black with some Prussian blue. Animal black, or bone black, contains about 10% carbon along with 84% calcium hydroxyapatite with smaller amounts of magnesium phosphate and calcium carbonate. Ivory black is a stable blue-black pigment that is denser than carbon black and has a good working quality for oil paints and watercolours. It is listed among the pigments used for colouring stucco marble in the nineteenth and twentieth century.
Synonyms: bone black; animal black; drop black; Frankfort black; German black, Pigment Black 9; CI 77267; Paris black; Elfenbeinschwarz (Ger.); noir d'ivoire (Fr.); abaiser
Wittenburg (1999); Museum of Fine Arts, Boston (2000)

Japan wax -  A pale yellow, soft vegetable wax obtained from the berries of the Japanese sumac tree, Rhus verniciflua. Japan wax is a by-product of lacquer manufacture. It is not a true wax but a fat that contains 10-15% palmitin, stearin and olein with about 1% japanic acid. Japan wax is sold in flat squares or disks and has a rancid odour. Japan wax is used as a substitute for beeswax.
Synonyms: Japan tallow; sumac wax; sumach wax; vegetable wax
Museum of Fine Arts, Boston (2000)

Jute - Long bast fibres obtained from the stems of linden plants, Corchorus capularis (white jute) or Corchorus olitorius (Tossa jute). Jute probably originated in the Mediterranean region and was taken to India and south-east Asia where it flourished. Jute has been used by man since prehistoric times. The pale brown fibres are soft, lustrous and coarse ranging in length from 4 to 10 feet. Microscopically, the fibres exhibit irregular, long cells with a visible lumen. Jute is composed of cellulose (69%), lignin (18-20%) with some uronic anhydride (4.5%). The brittle fibres are used to produce a thread called hessian. Jute becomes so weak when wet that a thin twine can be broken by hand. It turns brown and degrades with time, sunlight, water, acids, alkalis and bleach. 
Synonyms: Tossa jute; white jute; Indian jute; hessian; Bengal hemp; Calcutta hemp
Museum of Fine Arts, Boston (2000)

Kaolin - A group of hydrated aluminium silicate clays. Kaolins are primary clays formed by the weathering of aluminium silicates such as feldspars and nephelite. When pure, kaolin is a soft, white, absorbent powder. Impurities may give it a yellow, red, blue, grey or brownish colour. It occurs at many locations around the world (France, England, Germany, China, United States, etc.). Kaolin is used as a base for lake colours and as a filler in paints, cements and epoxies. Kaolin  (brick dust) has been used as an abrasive. 
Synonyms: kaolinite; China clay; bolus alba; porcelain clay; white bole; argilla; paper clay; brick dust; fuller's earth; white bolus; pipe clay; pipeclay
Museum of Fine Arts, Boston (2000)

Kaolinite  A_l2Si₂O₅(OH₄) - A hydrated aluminium silicate mineral which is the principal constituent of kaolin clay. Kaolinite crystals have a lamellar or plate-like structure that gives the clay its slippery feel. It is a natural alteration product of aluminium silicate rocks, such as feldspar. Pure kaolinite is a primary clay. Most secondary clays contain only a small percentage of kaolinite (Fournier 1996). 
Museum of Fine Arts, Boston (2000); Fournier (1996).

Keeneís cement/Keenís cement  - Patented by J.D. Greenwood and  R.W. Keen in 1838. It is a type of interior wall plaster obtained from gypsum. Gypsum is heated above 170°C to form anhydrous calcium sulphate. This was soaked in a solution of alum (potassium aluminium sulphate) to accelerate the set.  The mixture was then reheated to 400-500*C and ground to form a plaster. Because Keeneís cement sets more slowly than gypsum plaster it is easier to use; it does however set more rapidly than lime and produces a hard, smooth finish which can be painted or wallpapered within a few hours of application. 
Ashurst (1983); Trench (2000)

Kieselguhr - A German name for diatomaceous earth.
Synonyms: diatomaceous earth
Museum of Fine Arts, Boston (2000)
 
 

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