My system is not decent

Naturally, Chen Wenzhe's new work cannot be simple blue and white and multicolored. He plans to make a blue and white underglaze red elephant leg vase.

Decoration doesn't need to be too troublesome, just two dragons, one red dragon and one blue and white dragon.

It is easy to make a vase with elephant legs, and it is not difficult to paint the cloud and dragon patterns.

As for the blue and white material, use the best Qianlong blue and white.

If it is red glaze, it will be special.

Blue and white underglaze red, commonly known as "blue and white plus purple", is a porcelain decoration technique that uses underglaze red and painted patterns between blue and white.

Blue and white refers to the underglaze color that is painted with blue and white materials, then applied with transparent glaze, and fired at a flame above 1200C.

Underglaze red refers to the color material prepared with copper oxide (copper flower) as the coloring agent. Patterns are drawn on the green body (or the green body soil that is first applied with blue and white glaze), and then covered with a layer of blue and white glaze. The box is put into the kiln, and the high-priced copper is reduced to low-priced copper by a strong fire at 1250C ~ 1280C, showing a delicate and calm red pattern.

Doesn't it look very simple?In fact, it is not simple at all.

The most important point is to control the temperature.

When firing blue and white, only when the temperature reaches 250 degrees, it is best to control it below [-] degrees, so that the color will be the best.

If the temperature continues to rise, the blue and white color will darken and become dull, which is very unsightly.

However, the glaze made with copper flowers as a toner is in-glaze red, and the temperature required for firing it is higher.

Underglaze red is one of the traditional underglaze decorations in my country. It uses copper as a colorant to draw various patterns on the body, and then applies transparent glaze. The pattern is red, so it is called "underglaze red".

However, in order to make the underglaze red hair bright, the temperature must exceed 250 degrees, and it must not be higher than 280 degrees.

The underglaze red fired in the Yuan Dynasty used the color material containing copper oxide as the colorant. Jingzhen called this color material "copper flower".

It is prepared by heating copper to obtain an oxidized surface, which is carefully ground.

The color of this kind of color material is extremely unstable. Due to the different properties of the flame in the kiln, green or cyan, as well as various shades of red or even flashing purple appear.

However, in any case, the temperature must exceed 250 degrees, so that such color materials can develop normal color.

If the temperature is not reached, the hair color of the color material will be relatively dull.

Here, blue and white and underglaze red create a contradiction.

When the temperature is low, the blue and white hair color will be bright, but the red color in the glaze will be very dim.

When the temperature is high, the color of blue and white will be dull, but the color of underglaze red will be bright.

That's it, because it is very difficult to fire qualified products, blue and white underglaze red products are extremely valuable.

Human beings have a root of inferiority, that is, the more difficult it is to do, the more they want to do it, the more they want to get it.

Therefore, although the underglaze red is decorated separately, most of them are combined with blue and white for decoration, so it is called "blue and white underglaze red".

Its characteristics not only have the characteristics of "quiet, elegant, quiet and stable" of blue and white, but also add the grandeur of underglaze red, enrich the color effect, and form an elegant and simple artistic style.

Therefore, blue and white underglaze red porcelain has become one of the precious porcelain varieties in our country.

Judging from the existing archaeological and handed down materials, this kind of craft technology has a long history of mature development. After it was created in the Yuan Dynasty, it developed slowly in the Ming Dynasty, and there were not many successful products.

The blue and white underglaze red craft in the Kangxi period of the Qing Dynasty has been restored and developed, and there are many products with successful color development.

The Yongzheng period was the most mature and stable period for this kind of underglaze color craft.

Most of the Yongzheng blue and white underglaze red wares handed down from generation to generation are bright and stable in color.

Although there were many blue-and-white underglaze red ware produced in the Qianlong period, the color rendering technology of underglaze red began to decline, and it declined again in the middle and late Qing Dynasty.

From this, we can know that blue and white underglaze red is difficult to fire, and the reason is not only the conflict between blue and white and underglaze red, because even a single kind of underglaze red is difficult to fire. success.

What we are looking at here is kiln firing technology, and what Chen Wenzhe is most afraid of is kiln firing, because he has master-level kiln firing technology.

It turned out that he didn't realize that kiln firing technology is so important, but through repeated developments, the kiln firing technology obtained became more and more comprehensive, and he discovered that this is the fundamental.

This time, he just thought of firing blue and white underglaze red porcelain, and once again acquired a lot of kiln technology.

How to burn a kiln is a technology, and controlling the temperature is a technology, and how to control the temperature to make the utensils in the kiln, or more precisely, how to make the colored materials in the kiln develop color, is even more a kind of extreme. technology.

In the firing of blue and white underglaze red, it is mainly to control the firing of copper flowers.

Copper flower, that is, copper oxide, is a very peculiar metal, which is green when fired with an oxidizing flame, and red only when fired with a reducing flame.

Under the reducing atmosphere, the copper oxide in the color material is reduced to cuprous oxide with a small proportion of oxygen, or pure copper without oxygen.

Like the high-temperature red glaze that also uses copper oxide as a colorant, the red color of underglaze red is observed under a high-power microscope as "existing in a suspended state of pure copper fine particles, and the diameter of copper particles is only about [-]/[-] mm. , similar to a colloid, and the color is different from that of ordinary metals".

This colloid "is yellow when it is very small, red when it is slightly larger, and blue when it is larger."

Therefore, in order to reduce copper oxide into suitable red pure copper fine colloids, it is very critical to grasp the nature of the flame in the kiln and the length of the reduction atmosphere when firing the kiln.

That is to say, the color material in the kiln firing process is red when the reduction effect is appropriate, and the color will be darkened if it is excessive.

It is purple, blue and green when fired with a neutral flame or an oxidizing flame;

If it is not completely melted, it will be squirrel or even dark purple.

If it is melted excessively, it will fade into orange-yellow or white.

In addition, copper is above 800c, which has the characteristics of easy flow and volatilization.

During the high-temperature firing process, it will melt with the surface glaze and overflow the body through the glaze bubble.

Therefore, only a small amount of copper is enough to show red color, and the color is the best when the copper content is below 0.5%.

Therefore, it is also very important to control the copper content in the color material.

The firing temperature also has a great influence on the color development of underglaze red.

If the temperature is too high, all the copper will volatilize, and if the temperature is too low, the glaze will be dull, and the red color will not appear bright red.

Generally, the temperature above 1200c is more appropriate, and the highest temperature should not exceed 1280c.

In order to avoid the volatilization of copper, the middle and high temperature stage of firing should not be too long, so the choice of kiln position is also very relevant when firing the kiln.

It can be seen that the production of underglaze red, from the preparation of color materials, to the nature of the flame when firing the kiln, the temperature, the time for reducing the atmosphere, and even the selection of the kiln location, will affect whether the product can present a pure red color. make an impact.