S. (saffron - silicate paint)

Saffron - A natural, golden yellow colorant obtained from the orange stigmas of the Crocus sativus flower native to the Middle East. Saffron was introduced to Europe through Spain in the 8th century. The deep yellow to orange colour in saffron is primarily due to crocetin. It is extracted by boiling the dried flowers in water. The transparent colorant was used as a watercolour pigment and a tint in varnishes. It is listed among the pigments and dyes used for colouring stucco marble in the seventeenth and eighteenth century.
Synonyms: crocin; karcom (Lat.); krokus (Gr.); azafran de Otono (Sp.); auripetrum colorant; red gold; Natural Yellow 6; CI 75100; safran (Fr.); Echter safran (Ger.); zafferano (It.); safraan (Dut.); French saffron
Wittenburg (1999); Museum of Fine Arts, Boston (2000)

Sand - 1. Granular material passing the 3/8" sieve, almost entirely passing the No. 4 (4.75-millimeter) sieve, and predominantly retained on the No. 200 (75-micrometer) sieve, and resulting from natural disintegration and abrasion of rock or processing of completely friable sandstone. 2. That portion of an aggregate passing the No. 4 (4.75-millimeter) sieve, and resulting from natural disintegration and abrasion of rock or processing of completely friable sandstone. Note: The definitions are alternatives to be applied under differing circumstances. Definition (1) is applied to an entire aggregate either in a natural condition or after processing. Definition (2) is applied to a portion of an aggregate. Most natural sands are at least 98% silica. Fine aggregate produced by crushing rock, gravel, or slag commonly is known as manufactured sand. Finer than gravel, sand is used as an ingredient in mortar and other traditional building materials. It is also listed as inorganic additive used for stucco marble preparation according to literature.
Wittenburg (1999); RS Means Building Glossary (undated); English Heritage (2000); Museum of Fine Arts, Boston (2000)

Sand finish -  1. In plastering, a textured final coat, usually containing sand, lime putty,  and Keene's cement. 2. A smooth finish derived from rubbing and sanding the final coat. 
RS Means Building Glossary (undated)

Sandstone - A sedimentary stone composed of grains of quartz sand, deposited following the erosion of older rocks, held together by  cementing material and compacted by the weight of overlying sediments. The cementing material may be calcium carbonate, quartz, clay or various forms of iron. The nature of the cementing material and the degree of compaction affect the hardness, colour, texture and durability of the stone; the size of the quartz grains and the presence of other minerals also influence the character of the sandstone. Because of its gritty texture sandstone has been used as an abrasive. It is mentioned as grinding stone for polishing stucco marble by repeated grinding and polishing, performed with the use of a lot of water and various grinding stones, including sandstone and pumice for the first and second grinding; serpentine, limestone, hornblende, jasper, bloodstone for dark surfaces and meerschaum for white surfaces.
Trench (2000); Wittenburg (1999)

Sap green - An obsolete lake pigment made from the juice of buckthorn berries (primarily Rhamnus catharticus), mordanted on alum. The primary colourant in R.catharticus is kaempferol, but berries from other buckthorn plants may contain rhamnetin or quercetin. 
Sap green is a fugitive dark, yellowish green colour that was used in watercolour paints in the 17th  and 18th  centuries.  It is listed as one of the additional pigments (?) used for colouring stucco marble in the nineteenth century.
Synonyms: bladder green; iris green; verd vessie
Wittenburg (1999); Museum of Fine Arts, Boston (2000)

Scagliola - Scagliola is an inlay work of various coloured, smoothed and polished stucco pastes.  Recipes from various written sources mention ìalabaster-gypsumî as the basic material.  The actual Italian meaning of scagliola is gypsum calcined between 130° and 170°C.  The name ìscagliolaî originates probably from a variety of gypsum (Italian: gesso) used -  selenite - a kind of gypsum made of transparent and translucent scales (ìscaglieî).  This mineral was known and used during the antiquity under the name of ìlapis specularisî because of the translucent, mirror-like surface. The scagliola technique was invented by stuccoists working in Bavaria in the 16th century. Italian artists working in Germany introduced Italianate designs. The technique appeared in Italy during the baroque period, with the cult of illusionism. It was used to imitate marble and was popular in the 17th  and 18th  centuries for architectural features. One of the most famous production centres of scagliola with marble imitation was Carpi in Italy. In the seventeenth century, ìscagliolaî was made using selenite or sericolite occurring in the Appennino Emiliano in Italy.  The selenite was put in an oven at 300°C until it was broken and could be ground with mortar and pestle into powder that was then sieved.  Adding water and animal glue (rabbitskin glue or parchment glue) retarded the set of the plaster and produced a thick paste that could be coloured. Additives included sand or marble dust, and lime. The mix was coloured with dry pigments and filled with coloured marble or alabaster chips. Veining was mimicked by dusting the surface with dry pigments. The surface was smoothed with a metal scraper. Once the plaster had set, the long process of polishing the surface with pumice stones and filling any voids with a plaster slurry was carried out. Finally the surface was rubbed with oil to produce a high sheen. Figurative and ornamental decorations could be made with this material, imitating at least to some extent the pietra dura technique in which stones are cut to form inlays, mostly on flat surfaces like e.g. altar tables. It was also used for ornamental panels and columns (Rowland and Riley 1981). For the decoration of larger architectural areas, the technique of scagliola was used to imitate natural stone rather than to recreate decorative drawings - this is, according to most sources, how stucco marble started to develop. Scagliola is softer than true marble and scratches easily. Inlaid scagliola, which resembles pietre dure, uses the same materials, applied over a rigid support such as slate. A solid background colour is laid down and the shapes to be inlaid are gouged out. Coloured is then pressed into the voids to build up the desired image and the surface is polished and oiled.
Ashurst (1983); Wittenburg (1999); Trench (2000);  English Heritage (2000); Museum of Fine Arts, Boston (2000)

Sealant - Any material used to seal joints and openings. Natural waterproofing materials, such as waxes and tars have been used since ancient times. Oil-based caulk, or putty, was composed primarily of calcium carbonate and drying oils. The first synthetic elastomeric sealant, developed in the 1950s, was composed of polysulphide (Thiokol). Butyl rubber sealants, also manufactured in the 50s, contained talc, calcium carbonate, polybutene, mineral spirits and adhesion promoters. The first acrylic sealant, developed in 1958, was a solvent curing product that included calcium carbonate, silica, solvent and plasticizer. Silicone sealants, introduced in the 1960s, contained fumed silica, calcium carbonate, ground quartz, carbon black, talc and plasticisers. Polyurethane elastomers provide good abrasion resistance. Latex caulks, available in the late 1960s, eliminated the use of organic solvents. They typically contain a polymer emulsion in water with calcium carbonate, plasticisers and other additives.
Synonyms: caulking; glazing; mastic; putty; Thiokol
Museum of Fine Arts, Boston (2000)

Sedimentary rock -  Rock such as limestone or sandstone that is formed from deposits of sediment consolidated by cementitious material and/or the weight of  overlying layers of sediment. 
RS Means Building Glossary (undated)

Selenite CaSO₄.2H₂O  - A kind of gypsum made of transparent and translucent scales (ìscaglieî).  This mineral was known and used during the antiquity under the name of ìlapis specularisî because of the translucent, mirror-like surface.  Selenite and sericolite, both occurring in the Appennino Emiliano in Italy, were defined/called scagliola in the seventeenth century in Italy.  The selenite was put in an oven at 300°C until it was broken and could be ground with mortar and pestle into powder that was then sieved.  Adding water and animal glue produced a thick paste that could be coloured. 
Wittenburg (1999)

Selenitic cement (selenitic lime) -   A type of lime cement that has had its hardening properties improved by the addition of 5-10% plaster of Paris.
RS Means Building Glossary (undated)

Semi-hydraulic lime -   A type of lime categorized intermediately between high-calcium lime and eminently hydraulic limes. When run to putty it is almost as workable as non-hydraulic lime, even though its hydraulic characteristics can be substantially reduced by soaking in water for several hours. 
RS Means Building Glossary (undated)

Septaria  - Conglomerate consisting of nodules of calcium rich clay (marl). Used as a building stone from Roman times and as a key ingredient in Parker's Roman Cement, between 1796 and circa 1850.    
English Heritage (2000)

Sgraffito (sgraffitto)  - A decorative technique used in various media, also known as graffito or scratchwork, in which layers of contrasting colours are applied to a surface and a design is scratched through the upper layer to reveal the colour beneath. The technique was practised in antiquity and was described by Vasari as being a quick and durable method for decorating building facades. In the renaissance, lime plaster, tinted with ash, was used as the under layer, and then covered with white lime plaster. Most sgraffito, especially two or three colour work, belongs to the last century. In the 19th century, the lowest, levelling layer consisted of Portland cement, above which a layer of cement coloured with earth pigments was applied. The final layer for indoor work was Parian cement; Portland cement was used externally. With all materials the layers are allowed to dry but not set completely before the design is cut in with an iron stylus or knife, used to peel away the upper layer. After the plaster or cement has set fully, areas of the design can be oil-gilded.
Trench (2000); Ashurst (1983)

Shellac - A resin-like secretion of the lac insect Laccifer (Tachardia) lacca (formerly Coccus lacca). The insect feeds on a plant and converts the plant juice into the resin and red dye exudate. Shellac comes from India and some parts of Myanmar (formerly Burma) and Thailand. The crude lac, sticklac, is gathered from the trees and crushed as graded. The raw lac is washed, heated and drawn out into thin sheets. Once cooled, the shellac is broken into small flakes for sale as flake shellac. The colour of shellac ranges from a pale yellow to a deep red. Shellac is soluble in alcohol and is used as a protective coating for plaster moulds and casts. Shellac was often adulterated with colophony (Doerner 1934). Shellac is listed as a substance used for coating the stucco marble in the twentieth century.
Synonyms: lac; lacca; gum lac; bleached shellac; lemon flakes; orange flakes; garnet lac; refined shellac; kiri; black buttonlac; buttonlac; sticklac; stick-lac; seedlac; kusmi; katki; kusmi; shellack; Diatite; Smiths Patent American
Wittenburg (1999); Museum of Fine Arts, Boston (2000); Doerner (1934)

Sicilian brown - An old name for raw umber 
Synonyms: raw umber
Museum of Fine Arts, Boston (2000); Mayer (1969)

Silica  SiO₂ -  Colourless crystals or white amorphous powder. Silica is widely available because it makes up one of the largest portions of the earth's crust. In its purest form, silica, or silicon dioxide, occurs as crystalline quartz. The more common, but less pure, forms are quartzite, sandstone and sand. The fossil form of silica is diatomaceous earth. All forms of silica are inert, unaffected by heat, insoluble in strong acids (except hydrofluoric) and slowly attacked by strong alkalis. Silica is not commonly used as a pigment, however, it is found in grounds, primers and wood fillers. Silica is used in the manufacture of glass, water glass, abrasives, ceramics and enamelware.  
Synonyms: silicone dioxide; silicic anhydride; quartz; silex; diatomaceous earth; flint; diatomite; sand; quartzite; sandstone; amethyst; jasper, chalcedony; agate; onyx; tridymite; opal; cristobaliteilica 
Museum of Fine Arts, Boston (2000)

Silica flour (silica powder) - Very finely divided silica; a siliceous binder cement that reacts with lime under autoclave curing conditions. The flour is prepared by grinding silica,  such as quartz, to a fine powder. 
RS Means Building Glossary (undated)

Silicate paint - A water-based paint containing a pigment with a silicon-containing binder such as sodium silicate or a silicon ester. Silicate paints have been used in murals and stereochrome paintings. 
Synonyms: sodium silicate; water glass; silicon ester
Museum of Fine Arts, Boston (2000)
 
 

Bibliography              Index