In the Yuan Dynasty, judging from the way Macang soil was preserved, we knew that this resource was very precious.
Because before use at that time, the Ma Cang soil was stored in special containers, and no waste was allowed.
The role of Macang soil was to combine it with porcelain stone, the main raw material at that time, in a small proportion to increase the alumina content in the soil, so as to ensure that large objects would not be deformed when firing.
Therefore, the amount of Macang soil used is not large, but even so, it is still very precious, which is worth studying.
If the formula is lost, that is, the processing technology of Ma Cang soil is lost, then how could Ma Cang soil still be used in the Ming Dynasty?
At least the porcelain fired in the early and mid-Ming Dynasty has obvious characteristics of Macang soil, which is very easy to identify.
This kind of fetus containing hemp soil is a very special phenomenon.
It means that there are many bubbles in the middle, or they break on the surface to form pits during drawing, or they are trapped in the soil to form small flat holes.
These characteristics can be clearly found in the cross-sections of Yuan blue and white porcelain pieces.
Yuan blue and white porcelain clay with the best processing quality is pure white in color, while those with lower quality are a bit gray, and those with lower quality are yellowish.
This may be related to the quality of the porcelain stone used, the proportion of Macang soil, or the firing process.
It cannot be ruled out that during the Yuan Dynasty, the kiln entrances in different places were different, and the soil used may not be exactly the same.
In any case, the Ming Dynasty must have mastered the production technology of Yuan blue and white.
Otherwise, the newly discovered Yuan blue and white flowers would not be considered Ming Dynasty blue and white flowers.
So why was the craftsmanship of Yuan blue and white flowers lost during the Ming Dynasty?
Is it really because Macang soil has ceased production? There is no way to replace it with other kaolin clays?
In other words, all the usable macang soil left over from the Yuan Dynasty has been used up?
This is not possible at all, because the Ming Dynasty also mined Macang soil in Macang Mountain and used the Macang soil they processed themselves to make porcelain.
Unfortunately, the difference between Macang soil and kaolin is not clearly defined in Sui Hou's Pearl, but there are methods for dealing with Macang soil.
Without this method, Chen Wenzhe really would not have the confidence to imitate the real Yuan blue and white.
Now Chen Wenzhe can only hope that the characteristics of Macang soil are really realized after acquired processing.
In ancient times, especially during the Yuan, Ming and Qing dynasties, they did not have scientific means to test Macang soil, and their understanding of kaolin was insufficient.
Therefore, they will only deal with Macang soil, because there are still some slight differences between Macang soil and kaolin clay.
The problem lies in this tiny difference. It is with this difference that after processing with their special methods, high-quality Ma Cang soil appeared, and Yuan blue and white flowers can be fired.
If we follow this idea to recreate qualified Macang clay, we need to purify it on top of the existing kaolin clay and add some elements.
In this way, the Ma Cang soil can be obtained, and then processed by the ancient Yuandai process, and finally the Ma Cang soil that can be used can be obtained, and finally qualified Yuan blue and white flowers can be fired.
This is Chen Wenzhe's plan. First, he must process kaolin to obtain Ma Cang soil, and then process the Ma Cang soil to make Yuan blue and white.
If Chen Wenzhe's idea is right, then he can truly make the ancient Yuan blue and white.
Of course, there are still many problems in the middle.
If there is no problem with the green material and tire material, then there is also the craftsmanship and glaze.
The craftsmanship, in addition to decoration, is embryo making.
In terms of billet making technology, billet drawing, billet printing, billet cutting and other methods were all used in the Yuan Dynasty.
Most of the fine Yuan blue and white utensils we see are drawn, which has also become the most important feature in the identification of Yuan blue and white carcass molding.
Using the blank drawing method, several sections are made in advance.
Lower part, upper part, mouth, etc.
After drying, glue it with mud strips and glue the bottom.
In the large tank, the mud strips are smoothed out as joint mud to prevent displacement.
Small utensils generally only have mud streaks squeezed out.
The manual drawing and forming method is an extremely superb skill, and even in ancient times it was not something that ordinary people could do well.
In addition to the drawing method, the printing method is also commonly used, which is to use molds to make four-, six-, or eight-square shaped utensils.
For example, square pot, six-square, eight-square plum vase or extra large round plum vase, etc.
This billet-making method is relatively neat, and is different from the manual signs caused by drawing billets.
The green tire method is to finely trim the green tire that has been formed but not yet dry.
In modern times, the drawing method is no longer dared to be used easily, and the printing method is mainly used to make large cans, plum bottles, etc.
It's just that the artifacts made in this way are thin and heavy, that is, they are much heavier than the real thing of the same volume.
The carcass formed by the drawing method in the Yuan Dynasty has a rough, hand-made smooth surface.
It cannot achieve the flatness of modern printing methods, and some surfaces are slightly ridged.
It also looks thicker, mainly because it is lighter than the imitation product of the same volume.
The most obvious thing is that many wide spiral marks are formed on the inner surface of the carcass during drawing.
These wide spiral marks are about the width of a finger and are slightly concave in the middle.
Among these wide spiral marks, some objects have dense and silky fingerprints of the artist, and of course, some are not obvious.
Fingerprint marks are different from the linear lines that circle closely together like instant noodles on modern imitation utensils.
If these can be done well, then there will be no problem with the glaze, tire quality, and craftsmanship.
At this time, the only pursuit is enamel.
The glazes of Yuan Dynasty blue and white are also different, because their successfully fired glazes are also unique.
The glaze of Yuan blue and white porcelain is very unique, and now there are three types: blue and white glaze, blue and white white glaze, and privy glaze.
The green and white glaze is a continuation of the Hutian kiln craftsmanship of the Song Dynasty in Jingzhen.
This kind of glaze is the most difficult to imitate among Yuan blue and white porcelain.
Its characteristics on Yuan blue and white porcelain are very obvious. First, the glaze layer is thick.
There is often glaze accumulation on the edge or bottom of the mouth, and in some places the thickness may even vary.
The fluidity of this glaze is very poor during firing, which is in contrast to the excellent fluidity of modern glazes.
Second, it is lake blue or lake green, both of which have different shades.
When viewed up close, within two feet, the glaze is transparent, bright, and has a milky texture.
Where the glaze is particularly thick, the glaze layer is generally thicker on the soles of the feet, with a semi-devitrification or devitrification feeling. The blue color is bright and green, which is very pleasing to the eye.
Then there is the blue and white glaze, the characteristics of this glaze color are also very obvious.
First, the bonding degree of the body glaze is very good, it is not easy to see the thickness of the glaze, and it seems to be one body.
At an appropriate distance, usually about 1 meter away, you will feel that the texture of jade is very strong, even the strongest among all enamels.
It is generally white with a little bit of green, reflecting more of the warm and moist feeling like white jade.
The last one is Privy Glaze, which is characterized by being white with a hint of green (slight blue and green), and has extremely strong covering power regardless of the shade.
The second is that the texture of milk and the texture of jade are both strong, and the third is that the thickness of the glaze layer is in the middle of the first two, that is, neither thick nor thin.
Among these three types of glazes, the first two are so difficult to imitate that many modern people have no way to imitate them.