Bone China Revolution
Bone china (or bone ash china) does in fact contain bones; thankfully not the human kind but usually cattle bones. And lots of them!
The production process involves the raw, cleaned, animal bone being heated in a kiln to about 1000°c. At this temperature it is reduced to a fine ash. This ash is then ground with water and finally mixed with feldspar and china clay. For the technically minded, bone china consists of 50% bone ash, 25% feldspar and 25% of the very best quality china clay.
This bone ash porcelain was first used at the London Bow factory in around 1750. The Chelsea establishment soon followed about five years later.
The main advantage of the bone ash mix was that it produced far greater stability and it was more workable for the craftsmen moulders and sculptors. Increased stability meant a saving in terms of kiln loss which was a major problem for many manufacturers at that time.
At this point in ceramics history, we see the emergence of Josiah Spode I, who launched his own factory in 1776. His son, Josiah Spode II, who took over from his father, is rightly credited with the eventual refinement of bone china into the quality we have today.
Spode’s greatest achievement was to experiment with the bone china mix and finally reach a near perfect combination of elements to produce the finest porcelain. He accomplished this by combining the normal, hard paste, porcelain constituents of china clay and feldspar with the refined bone ash.
This created a revolution in the English ceramics industry and sounded the death knell for soft paste porcelain production in England.
So bone china became the bench mark for English porcelain and this has remained so ever since Spode’s innovations. And, in fact, bone ash has hardly ever been used outside of the UK as European and US ceramic producers tend to prefer the hard paste porcelain as originally introduced by the ancient Chinese craftsmen.
The use of bone ash enables the manufacture of china pieces that are strong, white and with a unique translucency.
We all enjoy the benefits of bone china today and we really should be most grateful for the ingenuity and efforts of a certain Mr Spode!
If you want to know the value of your china figurine or any other antique/collectible, then get immediate access to an expert. Just click below.
