Thursday, February 11, 2010
Getting to Know Your Porcelain Collectibles
- Hard-paste (True) porcelain is composed of kaolin and petunse and fires at around 1450 °C. When fired, kaolin provides strength in binding the piece together, while petunse fuses into a natural kind of glass that gives this porcelain its smoothness and brilliance. The sturdiness of hard paste porcelain allows for tighter modeling and more robust shapes, even in very delicate designs.
- Soft-paste porcelain is composed of the same materials as hard paste, but is fired at a lower temperature (around 1200 °C). Soft paste tends to be more granular and porous since the component materials do not fuse together in the case of hard paste porcelain. The lower firing temperature provides some benefits, including a wider palette of colors for decoration. Also, the surface is somewhat less white or brilliant and has an almost silky or marble-like feel to the touch, which can be a preferred look, especially on human figurines.
- Bone China is comprised of the same ingredients as hard paste (petunse and kaolin) but with added bone ash. Bone ash contains lime and phosphoric acid which help in fusing all of the materials together and allow for a more stable final product, even at the lower temperatures required for soft paste porcelain. For manufacturers, this means less damage due to cracking in the kiln and less waste or rejects, thus less cost. In decorative terms, an item with at least 30 percent mixture of bone ash can also achieve a similar brilliance and translucence typically seen on hard paste, but at the lower production costs of soft paste. Bone China was first introduced in England in 1750, and is rarely produced in other European countries or the US.
Porcelain collectibles come in a wide variety of shapes and sizes, and can range in purpose from being lavishly decorative to being highly functional in your day to day lives. Most porcelain shapes are made by casting, throwing or being pressed into molds, sometimes going through further surface modifications such as carving, perforating, or embossing to achieve the final look. After the shapes are formed, they are commonly decorated with underglazes, glazes, painting or transfer printing (unglazed and undecorated porcelain is called Bisque).
As is the case with many ceramic items, after a porcelain collectible is formed, fired and decorated, it is usually marked by its maker. Ceramic marks, also called backstamps, are like fingerprints. They are a symbol of pride and workmanship of the maker and can often tell you origin, age and quality of the porcelain. Identifying these symbols is more than just reading a mark, it involves careful consideration of many elements to confirm authenticity.
Most porcelain marks on fine antique china are "underglaze"--meaning, they were applied to the piece prior to firing. For the first hundred years or so of porcelain production there were only two known pigments that could withstand the high firing temperature necessary: iron red and cobalt blue, with the latter being more popular.
Often times a piece of china will bear two marks: one beneath the glaze, indicating the factory that produced the blank, and the second above the glaze indicating the decorator of the piece.
It is good for dealers and collectors to practice caution when buying and selling porcelain items. The more prized the product by a certain manufacturer, the more likely it is that the maker’s mark has been imitated. On the flipside, an item with no mark at all could either be a recent reproduction or a one-of-a-kind antique piece!
Here are a few tips for distinguishing your porcelain marks and how to date them:
- Items made for export to the US after 1891 must declare the country of origin. Older items usually include the country as part of their overall trademark, or may be stamped in or applied near the maker’s mark. Many recent Asian imports bypass this legal requirement by using a sticker or label, which is often removed or lost.
- Using a magnifying lens, examine the porcelain mark around its edges...if they look too perfect and applied with industrial machinery, then they are probably recent. Most items made prior to 1950 had their marks applied by hand, so the stamps would wear out over time and the pressure at which they were applied would vary between workers. Older marks are not as crisp at the edges.
- The universal “copyright” symbol (the letter C enclosed in a circle) did not exist before the 20th century, so if a mark looks similar to an antique porcelain mark, but has this symbol, it is a new imitation mark.
- small, hand-written marks tend to be pre-1800’s
- printed/stamped marks in colors other than blue tend to be post-1850
- the use of “royal” before a company name tends to be used after 1850
- the use of the term “limited” or “LTD” appeared after 1860
Marks cannot always be solely reliable for identification since many were and are still widely copied. Look for other clues like modeling, coloring, and type of paste (which is best seen if the area around a “blowhole” on the bottom of a figurine is unglazed, or if there is a chip or broken section of the object). There will also be exceptions to the basic identification rules depending on the individual company.
For more information on your porcelains or other ceramic items, please call us or visit our store at: 5627 Sepulveda Blvd, Van Nuys, CA 91411. Our on-site art specialist can research your item and help your determine what it is!