P for Soft-Paste Porcelain
In seeking the secret of Chinese porcelain, France made its mark by creating a remarkable ceramic paste called soft-paste, though it did not contain the vital kaolin.
Result: €133,350
European admiration for Chinese porcelain led to what soon became a specifically Western product: a ceramic much in vogue for its whiteness and translucency. To achieve this, two types of raw ceramic paste were developed: “hard-paste” — the closest to Chinese porcelain as it contained a high percentage of kaolin — and “soft-paste”, containing no kaolin and consisting of frit (a glassy mixture) or a phosphatic mixture based on bone ash. Both pastes were shaped on a wheel or in a mold, and the resulting forms were left to dry. They then underwent an initial “biscuit” firing at 950-980°C to eliminate the excess water still present in the paste. When they came out of the kiln, the pieces had shrunk slightly, and were white with a porous surface. These porcelain biscuit pieces were now strong enough to be handled and decorated. Here, the two techniques differed in the type of decoration and the firing temperature. As the chemical composition of soft-paste cannot withstand the same temperatures as hard-paste (fired between 1380 and 1460°C) without breaking, soft-paste biscuit was covered with a lead glaze: a melting, glassy material enriched with lead oxide to make it transparent or slightly opaque, with pale yellow highlights. This glaze was fixed with a firing at between 1100 and 1350°C. After this stage, the piece had an impermeable, glossy, warm creamy white surface, ready to receive the painted decoration.
If the needle leaves no trace, the porcelain is hard-paste; if the surface is scratched, it is soft-paste.
Soft Palette
Like glaze, colors were created using vitreous enamels tinted with metal oxides. Similar in nature on soft-paste, background and decoration were amalgamated during a final firing at less than 900°C. This temperature softened the glaze without melting it — so that it remained the background of the decoration — and solidified the fragile metal oxides without burning them. These precautions were the key to the delicacy of soft porcelain, whose subtle colors had long been unachievable with hard porcelain, limited to a restricted palette that could withstand a high firing temperature. Colors thus provide an initial clue for distinguishing hard from soft porcelain. But in fact, all you need do is take a needle and lightly scratch the surface of a piece on the underside to find out the type of porcelain. If the needle leaves no trace, the porcelain is hard-paste; if the surface is scratched, it is soft-paste.
The French court was so taken with soft-paste porcelain that all the leading painters of the time were commissioned to decorate it.
Historical Porcelain
What posterity acclaimed above all was French soft-paste porcelain, even if Italy produced the first wares. The very rare Medici porcelain on a blue and white ground dates from between 1575 and 1587, and the 60-odd pieces listed today are now in museums. Nearly a century later, soft-paste porcelain was born again in Rouen, in the same colors, under Louis Poterat, who obtained a royal manufacturing privilege that expired with his death in 1696. However, the jealously-guarded recipe was discovered at Saint-Cloud, which produced creamy, ivory-toned pieces studded with metallic black dots. The factory was granted a royal privilege in 1702. Though soft-paste was not suitable for large-scale pieces, its malleability made it easy to produce scalloped or gadrooned shapes. At the time, France was the only European country making white, translucent porcelain, before the Meissen factory riposted in 1708 with the very first pieces of true hard-paste porcelain. By the middle of the century, six or seven Paris factories were producing small soft-paste objects like knife handles and cane knobs. In 1725, the Prince de Condé became the patron of a factory in Chantilly. Its products were characterized by mediocre translucency and a creamy hue, both due to the addition of tin oxide to the lead glaze. The factory was set up in the former Château de Vincennes in 1738, granted a royal privilege in 1745, and moved to Sèvres in 1756. Its naturalistic soft-paste flowers brought it considerable commercial success. They were sold mounted in garlands or arranged in bouquets on metal stems. They adorned all kinds of objects and were illegally copied by Parisian factories, while the factory licensed by the King imitated Meissen statuettes. In 1752, the first soft-paste biscuit figurines were invented in France, and this new white gold was used for diplomatic gifts. The court was so taken with soft-paste porcelain that all the leading painters of the time were commissioned to decorate it. By 1760, it was resplendent with its first gold decorations, but the honeymoon was not to last. Its rich palette did not prevent Sèvres from stopping its production between 1804 and 1887 in favor of hard-paste alone. It enjoyed a brilliant renaissance thanks to Art Deco between 1925 and 1930. However, other factories remained loyal to soft-paste, particularly in England with its bone china, whose phosphatic composition is still considered an essential aspect. But the Sèvres factory is soft-hearted, and still produces this very first French porcelain pieces, using a phosphate recipe inspired by the one created in the 18th century.
Also read P is for Hard-Paste Porcelain
Worth Seeing
Soft-paste pieces
from the collections of the Musée de Sèvres
and the Musée des Avelines in Saint-Cloud
DRAWINGS AND PAINTINGS – CERAMICS – ART OBJECTS AND BEAUTIFUL FURNISHINGS – TAPESTRIES AND CARPETS
Friday 22 January 2021 – 13:00 (CET) – Live
Salle 5-6 – Hôtel Drouot – 75009 Paris
Beaussant Lefèvre & Associés
