Unmet demand for porcelain and profitability of its production (at high prices in Chinese and Japanese) have led to the widespread emergence of porcelain manufactories. Moreover, under the patronage of the powerful (as we know them!). Louis XV banned (under pain of a fine of 6,000 livres) use gold or silver utensils, which started to produce coins. This measure has encouraged demand for its products Sevres, but left no descendants of French jewelry designs. Charlemagne, but paid for the patent, demanded that the Jews purchase Meissen ware in a round sum. All - in the name of marketing, ie to develop their own porcelain production.
However, European porcelain in quality significantly inferior to Chinese and Japanese, because he was not quite porcelain in the literal sense of the term. This porcelain is obtained by the full weight of sintering at a temperature of 1 350 - 1 380 degrees, which allows to obtain a white, thin, clear, transparent and strong enough crock.
His variation of mass Europeans fired in kilns, allowing temperatures to reach only 950 degrees, which do not allow to bake a lot and get a solid crock. This imperfection of the European masses forced to make additional (preliminary) firing, which excluded the painting from damp. China is (Japanese) mass froze in the sun for several hours. Shrinkage of European porcelain exceed 17%(in Chinese), making it difficult molding. This two-sided embossing products, Europeans substituted unilateral (overlaid on the outside), which led to yet another roasting and additional loads. When firing the European product weight lose shape or burst, unable to withstand the internal stresses. For complex products marriage reached 70-90%. The shortcomings have arisen boundary layer lead to cracking during firing blank enamel and enamel painting. When the firing temperature (due to upgrading furnaces, but in the absence of instruments to measure temperature), enamel, intended for earthenware, flowed. We had to create and other termoemali.
Paintings of European porcelain at the initial stage was a copy of Chinese designs - flowers and unseen birds.

The newly Manufactory at Sèvres (1745), originated and Manufacture in Chelsea, where for more than a transparent crock of mass added to the finished glass, and to improve the ductility (to improve the quality of molding and more subtle crock) burning bone. From this crock was the color of boiled milk, and the polufarfor Manufactory Chelsea got the name "bone china".
Technological advances Manufactory Chelsea, in my opinion, was getting bearable mass to produce sufficiently thin (about 3 mm) and transparent products, as well as obtaining the enamel colors of dark red roses, sparkling on a substrate of hollow tin of white enamel. This color was like a business card of Chelsea.
Such enamel later produced in Russia (window Enamel Khlebnikov).

Quoted figures marks Manufactory Chelsea (from its inception until its acquisition by manufacture Derby) contain enough contingent (in my opinion) the periods of their application. Photo stamps themselves, I could not find online or in literature available to me. I believe that the forum users to fill in this gap.