General
The history of soft-paste porcelain dates back to early attempts by European potters to replicate Chinese porcelain at a time when its composition was little understood and its constituent materials were not widely available in the West. The earliest formulations were mixtures of clay and ground-up glass (frit). Soapstone and lime are also known to have been included in some compositions.
Medici porcelain was the first successful attempt in Europe to make imitations of Chinese porcelain. Produced between 1575 and 1587 the body is a type of soft-paste porcelain, composed of white clay containing powdered feldspar, calcium phosphate and wollastonite (CaSiO3), with quartz.
Other early European soft-paste porcelain, also a frit porcelain, was produced at the Rouen manufactory in 1673, which was known for this reason as "Porcelaine française". Again, these were developed in an effort to imitate high-valued Chinese hard-paste porcelain.
As these early formulations suffered from high pyroplastic deformation, or slumping in the kiln at raised temperatures, they were difficult and uneconomic to use in mass. Formulations were later developed based on kaolin (china clay), quartz, feldspars, nepheline syenite, and other feldspathic rocks. Soft-paste porcelain with these ingredients was technically superior to the traditional soft-paste and these formulations remain in production.
Read more about this topic: Soft-paste Porcelain
Famous quotes containing the word general:
“As a general rule never take your whole fee in advance, nor any more than a small retainer. When fully paid beforehand, you are more than a common mortal if you can feel the same interest in the case, as if something was still in prospect for you, as well as for your client.”
—Abraham Lincoln (1809–1865)
“A constitutional statesman is in general a man of common opinions and uncommon abilities.”
—Walter Bagehot (1826–1877)
“Every writer is necessarily a critic—that is, each sentence is a skeleton accompanied by enormous activity of rejection; and each selection is governed by general principles concerning truth, force, beauty, and so on.... The critic that is in every fabulist is like the iceberg—nine-tenths of him is under water.”
—Thornton Wilder (1897–1975)