To identify the base of porcelain, you can look at it from many aspects.
For example, the feet of Jingzhen porcelain are usually shaved off after the glaze is applied.
In contrast, neon porcelain is glazed after it is fully formed.
Therefore, if you look carefully at the boundary between the outer glaze and the base of Xijiang porcelain, you will see that the glaze ends with a sharp tangent line, which is very different from neon products.
Among ancient porcelain products from the Ming Dynasty, many have traces of being shaved off.
Except for inferior products made in the Qing Dynasty, most of the cut feet were wiped with a brush or cloth.
Therefore, the sole surface of the foot always has a soft and smooth feeling.
If you look at the Qing Dynasty porcelain, there are some that are very similar to the Ming Dynasty products, but I have never seen any imitation of this kind of foot-cutting habit.
Although it is sometimes difficult to judge with the naked eye, it can be roughly understood if you use a magnifying glass.
When we identify Ming porcelain and Qing porcelain, although we can generally look at their shapes, glaze colors, patterns and other aspects, we sometimes get confused and don't know what they are.
At this time, if you can pay attention to this habit of cutting off the feet, it will become a powerful clue for identification.
In addition, there is also tire protection glaze.
The tire protective glaze is usually added with sesame-colored plant ash, which can protect the plain tire and facilitate even glaze application.
There is a big difference between the Qianlong and modern counterfeit celestial bottles in the protective glaze at the base of the rim.
Qianlong's tire glaze has been oxidized at high temperatures and is shiny, while the fakes have no sesame-colored tire glaze at all.
Then there are traces of tire soil. Old ones have a "hard" feeling with sand in the tire soil. Hand-drawn blanks form spiral patterns of different sizes and depths that will remain on the inner wall of the artifact.
There are two types of fake tires, artificial and machine-made.
The manually drawn tires have no traces of repairing them with bamboo knives, because they are repaired with iron knives.
Even the hand-drawn spiral pattern of the machine-made tire is not visible, and the tire soil is dense, powdery, and has no sandy feel, and is in a "soft, wet" condition.
These characteristics are still very obvious, but imitations that do not avoid even these are definitely low imitations.
This kind of thing has little value. It is a work of large-scale industrial production. It is cheap and easy to identify.
To truly make a high imitation, you still have to look for flaws in the subtleties.
For example, where the tire is exposed, the continuity of the tire glaze.
Where the old ware has no glaze and the exposed body is dry, the glaze forms a unified feeling.
The exposed areas of the new ware without glaze appear "wet", and the glaze forms the visual impression of two parts.
Even if the utensils have been specially aged and treated, they will not be able to show the visual appearance of the glaze being connected as a whole.
Due to the weathering of the years, the feet of old utensils will form uneven bumps and pits to varying degrees.
The overall appearance shows a natural, dry and unified color.
The wetness of a new vessel may appear like it just came out of the oven, or it may become too dark or too old due to chemical forgery, and the whole may not be unified, giving the "wet" feeling of separated glazes.
In order to reduce costs, mid- to low-end imitations are all produced using mechanically processed raw materials. Their exposed soles are either too white, too thin or too dense.
In fact, it is easiest to see the exposed tire clearly by looking at the fragments.
The benefit, or one of the advantages, of studying porcelain shards is that you can observe the body of ancient porcelain very clearly.
Since it is a fragment, its cross section exposes all the information about the device.
Including tire thickness, color, pore status, particle status, tire quality purity, impurity status, water absorption performance, hardness, etc.
There are obvious or subtle differences in the information about these wares in different eras and at different kiln entrances. This is an important perspective for the identification of porcelain.
However, this information is difficult to fully disclose.
The entire vessel is basically covered with a glaze layer, with only the "tip of the iceberg" exposed on the bottom contact surface (outer bottom, foot end) and the glaze leakage and glaze shrinkage areas.
Moreover, what is disclosed in these limited "exposed areas" is often not the real information about the porcelain tire, but is often an "illusion".
It is often pottery (cosmetic soil), oxide layer (flint red), acid and alkali corrosion layer, mildew pollution layer, dirt accumulation layer, etc., which are not the true fetal color.
For example, the attachments to the feet are different between modern times and ancient times.
At present, in Jingzhen, petroleum liquefied gas kilns are commonly used to bake porcelain.
In order to prevent the objects from adhering to the silicon carbide shed board, quartz sand or alumina powder should be sprinkled between the two.
Carefully observe the foot ring of the utensil. If the above two materials are glued on it and are very strong, it must be a modern imitation.
This is not only true for Yuan blue and white, but also for Ming and Qing porcelain.
In ancient times, quartz sand and alumina powder were not used as bedding materials at all.
From this we can see that there is a lot of knowledge involved in just identifying the base of a piece of porcelain.
If these characteristics are perfect, then look at the deeper technology.
There are several steps in the process of making porcelain.
For example, trim the glaze around the feet!
The official kiln porcelain of the third and third dynasties of the Qing Dynasty, especially the official kiln wares of the Kang and Yong dynasties, pay special attention to the glaze around the edge of the foot ring.
After glazing, trim the top and inside of the foot circle to make the glaze on both sides of the instep neat.
And only less than a millimeter of tire is exposed.
The overall neatness and fineness are very fine, which cannot be achieved by ordinary folk kiln products.
Use a knife to lightly trim the glaze on both sides of the instep.
Let a white tire protrude between the tire and the glaze, and the protruding part (unglazed part) is less than a millimeter.
This delicate craftsmanship, neat and beautiful, is a standard for identifying official porcelain of the third dynasty of the Qing Dynasty.
The body quality of Kangxi porcelain is fine, white and firm, but the porcelain making style is relatively rough, with spin marks left on the bottom of the vessel.
Because the tires are artificially washed, there are still impurities no matter how fine they are.
Therefore, there are some black spots on the glaze on the bottom of the vessel.
If something you come across is written as the Kangxi model, but the bottom of the vessel is smooth and clean, with no rotation marks or black defects, it is most likely a later imitation.
Taken together, many imitations have irregular soles and rough edges, and you can feel the stiffness of the rotation marks.
The soles of the feet are coarse sand and not smooth.
The glaze bond is also loose and the glaze surface is thin and turbid.
In the sole of the genuine product, if it is a blue and white model, you will definitely be able to see bubbles under a magnifying glass, but there will be no bubbles in the imitation product.
Of course, these are all superficial. If you want to imitate Ming Dynasty porcelain well, you must look at the soil.
Comparison of fetal soil raw materials is the most important identification method.
The texture of old porcelain is made of decomposed old soil.
In addition, the old porcelain has been aged for a long time, and to the naked eye it looks dry, crispy and has signs of aging.
The mud-making process of new porcelain bodies is different from that of old porcelain. First, the ratio of raw materials is different, and second, the porcelain clay is crushed by a mushroom machine.
Therefore, modern porcelain bodies may appear to have a tingling sensation when touched, and although some do not irritate the hand, they may feel wet and hard.
Take the glutinous rice embryos of the Qing Dynasty as an example. If you compare a grain of rice with a grain of glutinous rice, the rice will be wet and hard, while the glutinous rice will be dry and crispy.
However, please note that there were many kiln openings in ancient times, and the quality of the bodies varied greatly, so one cannot cover them all.
The simplest way is to use a piece of old porcelain and a piece of new porcelain to compare, slowly experience it, find out the difference, and you will be able to understand it.