Pottery, blue glazed

FIGURE 16.7 Many vanadium Loni ioundt torm vividly colored solutions in water. The are also used in pottery glazes. Tine blue colors here aie due to the vanadvl ion V t) ... 

This oxide is used in making blue and green colored glass and in glazes for pottery, but in recent years the preparation of superconducting materials such as YBa2Cu307 has become a serious interest. Other materials containing mixed oxides have also been produced. 

Clark, R. J. H., Curri, L., Henshaw, G. S., and Laganara, C. (1997). Characterization of brown-black and blue pigments in glazed pottery fragments from Castel Fiorentino (Foggia, Italy) by Raman microscopy, X-ray powder diffractometry and X-ray photoelectron spectroscopy. Journal of Raman Spectroscopy 28 105-109. 

FIGURE 16.10 Many vanadium compounds form vividly colored solutions in water. They are also used for pottery glazes. The blue colors here are due to the vanadyl ion, VOz+. 

A different problem related to Sevillian pottery is that several specimens are not considered to be true majolica, but rather a lead-glazed pottery. A few of these samples have been considered in the present study, five of which are clearly of a Sevillian origin (2 honey samples, 2 green samples and 1 blue sample). Moreover, as discussed above, XRF indicate that five of the 7 ungrouped samples could be Sevillan products, but contain significantly lower concentrations of CaO and Sr. All... 

This oxide is used in making blue- and green-colored glass and in glazes for pottery. 

Cobalt dyes have been used for centuries. Craftsmen used materials from the earth to color glass, pottery, glazes, and other materials. Cobalt minerals were especially prized for their rich blue color. 

Flow Blue. A deep cobalt blue which was used for under-glaze printing on pottery. As the name indicates, the colour tended to flow into the glaze, giving a blurred effect this result was obtained by placing flow powder... 

Flow Powder. A mixture formulated to evolve chlorine at the temperature of the glost firing of pottery and used in the production of flow blue (q.v.). For ware covered with a lead glaze, a suitable composition is (per cent) NaCl, 22, white lead, 40 CaCOj, 30 borax, 8. For use with a leadless glaze a suitable mixture is (per cent) NaCI, 15 MgCl2, 55 KNO3,15 CaCOj, 15. 

Littler s Blue. A royal blue first produced in about 1750 by William Littler of Longton Hall, Stoke-on-Trent, by staining white slip with cobalt oxide, applying the slip to pottery-ware, firing, and salt-glazing. 

Peach Bloom. A glaze effect on pottery produced by the Chinese and characterized by its soft pink colour with patches of deeper red. It is achieved by the addition of copper oxide to a high-alkali glaze but requires very careful control of the kiln atmosphere the bloom results from incipient devitrification of the glaze surface. Peacock Blue. A ceramic colour made from a batch such as 33% Cobalt oxide, 7% standard black (q.v.), 45% China Stone, 15% Flint. 

Thenard s Blue. A dark blue colour for use under-glaze in pottery decoration it consists of approx, four parts cobalt oxide to five parts alumina. 

It is listed by the Colour Index (1971) as Cl llhAb. Cobalt blue as a pigment shonld not be confused with cobalt blues used as glazes and enamels in pottery decoration. The compositions of similar amorphous vitreous materials are discussed imder smalt. 

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