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Collecting Newsletter, Issue #002 -- Collecting Tips and Information May 13, 2015 |
Newsletter 02-2015
Content
Blanc-de-Chine is the name the west has given to white porcelain
hundreds of years ago
The early Blanc-de-Chine porcelain was far from a pure white. Early white porcelains were anything but snow white. It could be termed as milk white, ivory, etc. but it was not (emphasis) pure white. Basically, monochrome white porcelain consists of white clay and white glaze. If the clay has an even slightly different color, like a tint of gray, brown or other, then the resulting glaze is reflecting this after firing with a different hue. Early whites, like the white porcelain of Ding kiln, usually had a tint of yellow. Even the wares of Dehua kiln, which later became the best known representative of Blanc-de-Chine, had a yellowish hue in the Ming dynasty. Holding a slightly translucent piece against the sun shows often a faint reddish hue, however. Only in the late Qing dynasty did the Dehua white wares become almost pure white. That means, only then was the clay white enough that Dehua did become to represent Blanc-de-Chine (china white) in the very sense of the word. This is due to its clay. Unlike some other kilns, the clay mined in the area of the Dehua kiln is already very white at the source, the whiteness is not the result of purification of the kaolin clay.
The same that is said above is basically also true for the white base of underglaze blue and otherwise decorated wares.
These wares
do not normally have a white glaze per se, but they appear white
because after firing the white clay is visible as such through the
translucent glaze. If the clay had a different color, the glaze
appears darker, with a different shade of white. Thus again, the
whiteness is
dependent on the purity or whiteness of the clay. The clay was usually purified over a period of one year (two years for imperial porcelain). This involved treading it by foot, beating it with hammer-like devices driven by a water wheel, fermentation, flushing away foreign matter, etc. until the clay was considered good for use. The clay was then shaped into bricks and stored for later use.
Only in the
late Qing dynasty, approximately the very late Guangxu reign, would
it have been possible to find a pure white porcelain. Before that,
porcelain glazes would show one of several hues, like for example the
one called "duck's egg" color by the Chinese. The white glaze of the porcelain should usually have an ever so slight shade of blue, gray, yellow, green or even pink. If you are not aware of this, just take a sheet of white printer paper and hold it besides a piece of porcelain. You will see the difference! I can definitely confirm that this is not just talking - I restore antiques and have to replicate glazes of porcelain. There is never any snow white glaze coming with any Chinese antique. Such a glaze is almost always a sign that a piece was made in the 20th century. So what has this to do with you? You can use this information directly to detect authenticity problems. In the world of fakes we live in nowadays, this information is one of the factors you should take into consideration when evaluating whether or not to buy an antique. Anything that has a snow white glaze is suspect - it is very likely either from very late in the Qing dynasty or later in the 20th century. And yes, all what is said regarding monochrome white glazed items above is also valid for blue and white porcelain, even if the glaze may have a different composition. For example, if you see an early 19th or even 18th century underglaze blue decoration, but the item has a snow white glaze, no matter what, it is more likely a later imitation or fake than the genuine thing.
Applied
Terminology
(usable for age verification) Orange
glaze line This
is a
thin orange or reddish brown line that can appear near the foot
along the edge of the glaze (it
is on the unglazed, fired clay). It appears on porcelain made in
private kilns (minyao), but not on imperial porcelain. This can be an important point when evaluating age of porcelain, but please be aware that not every type of porcelain/glaze does develop this. Slip Slip is basically a clay solution thinned with water. It is mostly used on more ancient porcelain items (Yuan dynasty or earlier), which had a relatively rough, porous porcelain body. Not every type of ancient porcelain does have it. Before any decoration could be applied to the surface of porous porcelain it was necessary to cover the minute pores with a filler - that is slip. This prevented that the glaze or decoration could be absorbed by the clay. Slip should always be present in Tang sancai and Liao sancai wares. If there is none, then the item's authenticy is doubtful.
Orange peel accurately describes the look of the glaze of some porcelain items made between from the Daoguang reign to the end of the Qing dynasty, and during the Xuande reign of the Ming dynasty.
It
is not the rule, however, that this glaze must be there, but its
presence may affirm that an items ifsfrom that period. The glaze is
the result of the kiln environment or temperature. Wave glaze The same as the above, only that the glaze has a wide, wave-shaped surface
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Faking related:
High-quality monochrome porcelain fakes Porcelain made during the Yongzheng reign (Qing dynasty, early 18th century) results frequently in high auction results; thus fakers try their best to make high-quality copies. They have the chemical composition of the color layer of authentic porcelain analyzed and replicate the colors. As a result, the fakes highly resemble the originals, and it can be difficult to recognize them as fakes. However, the inside of bowls is often more glossy than the originals of the Yongzheng reign.
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