Blanc fixe
Description
A synthetic white pigment prepared from precipitated Barium sulfate. Blanc fixe is a fine powder that was manufactured and sold as a permanent, stable white pigment from about the 1820s. The pure white powder is transparent when used as a filler or base for lake pigments. The reproducible whiteness of high purity, synthetic barium sulfate has led to its use in the standard white tiles for reflectance spectrophotometry. In photography, barium sulfate is used as the white base for color prints because it provides good transparency as a dye base thus producing true colors.
Synonyms and Related Terms
barium sulfate; Pigment White 21; CI 77120; Barytweiss (Deut.); blanco fijo (Esp.); sulfate de baryum (Fr.); bianco fisso (It.); baryta white; mineral white; enamel white; permanent white; constant white;
Risks
Nonpoisonous
Physical and Chemical Properties
| Density | 4.36 |
|---|---|
| Refractive Index | 1.62 - 1.64 |
Microscopic Properties
In plane polarized light, the synthetic variety appears as fine grained, colorless particles that have a rounded or bacterioid shape. Relief is low, since the RI is close to 1.622. Under crossed-polars, birefringence is low with first-order grays observed. Very fine particles may appear isotropic.
Additional Images
Barium sulfate reference (Fezandie & Sperrle), PPL, 400x
Barium sulfate reference (Fezandie & Sperrle), XPL, 400x
Resources and Citations
R. Feller, "Barium Sulfate", Artists Pigments, Volume 1, R. Feller (ed.), National Gallery of Art, Washington DC, 1986.
- Eastaugh, N., et. al. The Pigment Compendium: a Dictionary and Optical Microscopy of Historical Pigments, Butterworth-Hienemann, 2008
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
- R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 84
- Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
- Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985