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Collecting Newsletter, Issue #002 -- Collecting Tips and Information
May 13, 2015

Newsletter 02-2015


  • White porcelain & white glazes

  • Scrap book notes (hints and tips that do not warrant a web page or an article on their own)

White Porcelain & White Glazes

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.
The best idea of what 'pure' means would be calling it snow 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.
Impurities within it, or mixing of kaolin clay with gray or other clay colors will result in a darker white. Really pure white glazes will hardly ever be found in porcelain items made before the end of the Qing dynasty. The only exception may be imperial porcelain, because the clay of those was subjected to a much longer refining process than the average clay used by private (minyao) kilns. More of the impurities were removed as a result of this preparative treatment of the clay. The object of the whole was removing as much iron or iron oxide content as possible, both from the clay as well as the glaze, as iron would result in a darker color.

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.
Well ... I have had difficulties imagining THAT color at first, although I had already eaten duck eggs for years. :-)

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.

Notes from my scrap book
Tips and hints from my scrap book, accumulated over the years in an unrelated order. These tips may not be worthwhile a web page, but many contain information that is not mentioned in any books, or literature. Some of these bits of information are relevant for more advanced collectors.

Applied Terminology (usable for age verification)

Orange glaze line
火石紅 - English term unknown)

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.
It is caused by iron content in the glaze, on porcelain that is usually 150 years old or older.
How it develops: The glaze contains iron (oxide); during the firing in the kiln the edge of the glaze retreats a tiny bit. This leaves some of the iron absorbed in the fired clay. Over a long period this turns red or orange, resulting in a fine line along the edge of the glaze.

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 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 glaze

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


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.


  • China Porcelain Making in Pictures
    I have found this series of old paintings to be an excellent overview over the manufacturing process in ancient China.

  • Link to porcelain in the National Palace Museum, in Taipei:

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