Tao you inquired about the purple pottery that he bought. Compared with other parts of the green body, the calligraphy and painting parts of the carving decoration are not smooth, most of them are slightly convex, and the calligraphy and painting parts themselves are not smooth. They doubt whether they have bought the defective products.
In fact, this kind of situation is exactly the trace left by the carving decoration process. Why is it difficult to decorate the parts as flat as other parts? It is mainly caused by the following three reasons:
The first reason is that the nature of the clay used for engraving and filling is not the same as that used for the body itself, so it is difficult to integrate the clay into the green body, and there will always be more or less traces.
Moreover, it is precisely because of the different nature of the clay that many potters are troubled by. The most common problem is the edge cracking of the filling picture, which is the most headache for purple pottery artists.
The second reason is that the properties of the mud are different, and the shrinkage rate of the two materials is different when the temperature is higher than 1100 ℃. Therefore, even if the engraving image is refined to be as smooth as other parts of the green body, there will be two results due to the difference of shrinkage rate during the firing process
One is the case of partial bulge, that is, in the process of shrinkage, all parts of the green body squeeze each other, so that the engraving part and even other parts will have slight bulge; the second is the situation of partial depression. Due to the different properties of the filling mud and the blank mud, the shrinkage rate is also different. If the shrinkage rate of the green mud is greater than the shrinkage rate of the cutting clay, they will tear each other Crack, slight dent, severe crack.
The third reason is caused by many times of engraving and filling. The decoration of some purple pottery works needs to be completed many times. Each time, the clay filled in is different from other materials. Therefore, after many times of filling and firing, it is very easy to appear uneven phenomenon.
The actual situation is that more than 95% of the purple pottery decorated with engraving patterns are not completely flat. This is the result of the comprehensive formation of Jianshui purple pottery’s clay property, technology and shrinkage rate, which belongs to the inherent characteristics of purple pottery.
Therefore, the purple pottery with uneven filling position is not a defective product as long as it does not crack and has no serious bulge or depression.