I visited China a few years ago while my father was working at a nuclear plant, and I picked up a few pieces of eggshell porcelain. I am in 10th grade and I am doing a report on eggshell porcelain and found your website and would like to ask for additional information. Generally, anything you have on eggshell porcelain would be appreciated. Specifically, my report is broken into manufacturing, history and dating. If you have any other sources of information on eggshell porcelain, I would appreciate it.
It would take *me* a month to write that paper - are you sure you have picked a subject you can land? :-)
However, I will give you a basic structure.
The first instance of "eggshell" if we by that mean absurdly thin pottery dates back to prehistoric times. The big jars of the Gansu Painted pottery in the mid- to north western Yellow river area, are way much thinner than they look and some feels like paper in the hand. They were built by hand by ring modeling.
Also the Longshuan Black Pottery, in the mid- to north eastern Yellow river area, that also dates some 2000 years B.C. are of paper thinness, but they had invented the potters wheel that seems to have helped some.
Next big stop for "eggshell" is Song Dynasty and - then we are closing up on porcelain. In Hutian village, close to Jingdezhen, in southern China, mid Yangtze area, where true porcelain were soon to be made - they made eggshell porcelain in a somewhat softer clay and glazed it in a bluish white glaze called Jingbai. The only difference between this "porcelain" was that the clay does not seems to have had any extra Kaolin added for strength but were a natural clay made of pure Chinese "porcelain stone" found in the area.
Next stop is, I think Bushell in "Oriental Ceramic Art", who mention one of the first Ming emperors (Yonglo) who are known to have Porcelain of eggshell thinness made - so called bodiless ware.
During Qing dynasty eggshell thin pieces were also popular during the Yongzheng 1723 -1735 period. There were tea cups and saucers, and plates often with a "ruby back", but their bodies of the same thickness were less translucent.
The production of modern eggshell porcelain started around 1916 during the period of Hongxian (1915-1916). Also in Jingdezhen. In the planning of his official Imperial ware they settled for looking at the Yongzheng period as a model for the decoration after first having considered the Song dynasty.
During the 1920-30 eggshell ware became an important part of the total production program in Jingdezhen with well over 3300 men occupied by 1928. A serious break in production took place when the Japanese took Jingdezhen in 1937 after a surprise attack on Shanghai in 1932, the most important export harbor city.
Eggshell thin porcelain is still made up to this day, most of it decorated with enamels. Most of the less expensive pieces have their borders added with transfer prints and only the main decoration is painted by hand.
Regarding the manufacturing technique it is hard to get any information from the Chinese. I have tried to figure this out by myself though, by "snooping around" among the porcelain factories in Jingdezhen - i.e. done my own research.
The raw porcelain clay piece seems to be molded in a carefully made plaster of paris mold. That mold in itself I think is done from a steel model of the piece they want to make.
The molding itself is done by pouring liquid porcelain clay into the mold. The mold then soaks up moist from the liquid clay which then forms a thin clay skin that adheres to the inside walls of the mold. The remaining still liquid clay is then poured out of the mold.
After a while the mold is opened and the clay body of the piece is then cut and carefully sanded down to it final thinness.
This is made only by very experienced potters who judge by the sound from their knife how thick the clay walls of the porcelain piece are. If this is really the case I have not been able to have confirmed. But, as far as I know this is it. No tricks, only lots of hard work.
Further information on manufacturing techniques and all dates regarding emperors and dynasties can be found at my web pages under "HISTORY" and "PORCELAIN". Also some examples of eggshell porcelain can be found among the "Q&A" pages.
I think this is as far as I can help you. I would be most grateful for a copy of your paper though when you are finished.