Key Points and Difficulties in the Identification of Blue-and-White Porcelain in Different Period

China is a world-famous ceramic kingdom.

As early as 8,000 years ago in the Neolithic period, our ancestors have learned to make and use pottery.The appearance of porcelain is also the crystallization of the great creation and wisdom of the laboring people, craftsmen and entertainers of our country.Especially, the combination of exquisite workmanship and long-standing traditional culture makes it stand permanently in the forest of the world, which is rare in the history of world science, technology and culture, and is always worthy of admiration, study and pride of the Chinese people.The history of Chinese ceramic craft is an important part of ancient Chinese politics, economy and splendid culture. It is a history of spiritual civilization and material civilization.It not only embodies the pursuit of Chinese people’s life style and aesthetic taste, but also reflects the level of social production and the change of human being in nature.Therefore, the generation and development of China’s ceramics have made remarkable contributions to the progress of human civilization.

In our country, the history of the development of ancient arts and crafts is much earlier than other cultural origins.The history of a country should have been studied and written by its experts and scholars themselves.But for thousands of years, the feudal rulers did not attach importance to the development of science and technology, so-called development and innovation of science and technology, only craftsmen or craftsmen matter, and the Jiangshan society;Therefore, the research works on the development of ancient Chinese science and technology and the development history of ceramic technology are very little, and all the written expressions are only preserved in some articles or works of scholars.This is clearly out of proportion to a country with a long history and culture.Over the past 100 years or so, China’s cultural relics and works of art have left the country in large numbers, and there have been very few publications at home and abroad.And domestic museums, academies, research institutes can display only a small part of it.Therefore, the study can only be based on only a small number of objects and pictures can be seen, the information can be said to be limited, the results of the study can be imagined.On the contrary, foreign scholars have a lot of detailed articles and works in this field, such as” History of Chinese Science and Technology “by Dr. Joseph Needham, a famous British scientist, which expounds the development of ancient Chinese science with unique vision. And the impact on the development of world science and technology.With the founding of New China, especially since the reform and opening-up, the national economy has been booming, the people’s living standards have been constantly improved, while the material life has been continuously satisfied, the cultural and spiritual needs of people have become increasingly urgent, as a Chinese, “Ceramic country and do not understand language porcelain”, “living porcelain country and do not understand porcelain learning”, “then our party (peer) shame also”.Therefore, understanding history, carrying forward national culture and protecting historical and cultural heritage have become a new subject for people nowadays.

Now, when we turn over the history of Chinese ceramics, serious study of the production of ancient ancestors of ceramics, in different periods of the use of different materials and decorative objects found that no decorative effect can achieve such a blue-and-white porcelain, the great impact on later generations;The development of blue-and-white porcelain and the use of cobalt materials, as well as the influence of cobalt materials in different periods on the decorative art style of blue-and-white porcelain, play a more or less important role for us to learn, understand and identify the artifacts of different periods today.

First of all, natural water is a spinel (CoOAnO3), a compound of manganese dioxide, cobalt oxide and other oxides, viewed from the outside as black lumps or granules.It has excellent heat resistance, among which cobalt has strong coloring force and is blue after being fired by kiln.Therefore, it is used to make blue flowers, blue glaze raw materials.(cobalt 60 is a radioactive isotope and is widely used in scientific research. )

Blue and white (cobalt) color three elements include: Ash, manganese, iron.

Cobalt is blue;

Manganese is purple;

Iron is brown and black.

Cobalt-earth deposits are widely distributed in China. Cobalt-earth deposits are produced in Jiangxi, Zhejiang, Yunnan, Fujian, Guangxi, Guangdong and Sichuan.Because cobalt earth is not buried deep, it is easy to mine.Therefore, the use of cobalt materials from different places of origin to burn blue-and-white porcelain has become one of the important basis for identifying the age and authenticity of blue-and-white porcelain.In the course of the study, we found that 0.25% cobalt oxide in the glaze can fully show moderate blue;0.5% cobalt oxide is showy blue in glaze.1% cobalt oxide shows a very deep blue color in the glaze.When cobalt oxide is slightly higher than 1%, it appears blue-black or black.Therefore, it is very important to choose cobalt-earth ore as the painting material of porcelain decoration.When the required cobalt material is collected, it must be washed, packed, calcined, picked, and ground to make positive and secondary materials.Standard material (top material) used to describe the color of blue and white materials, that is, green materials, also known as cobalt materials.of inferior material) used for colour-matching glazes.

China’s use of cobalt blue has a long history, from the archaeological data, as early as the Spring and Autumn Period, Warring States Period (770-221 BC) on the ceramic beads have appeared cobalt blue;After analysis, it is found that there are many aluminum elements, which belong to the aluminum-barium system. Its discovery has a great influence on the later glassware in our country.But there was a clear difference from the sodium-calcium glass of ancient Egypt and the West, which used cobalt blue as a colorant in perfumery bottles made in Egypt in the fifteenth and fourteenth centuries BC.In addition, the first use of cobalt oxide colorant for color decoration, so that the beautiful blue image of the object is not China, but the Arab Iran, Iraq, Syria, Turkey and other places;A soft pottery made from the 9th to 14th centuries AD and baked in a furnace with a simple cobalt oxide pattern on the glaze after an opaque white glaze containing tin oxide is covered in a dark-colored tread.Many of these excavations are local, suggesting that cobalt blue is widely used.It is worth mentioning that, on October 24,2018, the fall auction of Sotheby’s in London, England, “Islamic Art” special auction, a rare Turkish Iznik blue and white flower glaze pottery plate, estimated at ￡300,000-500,000. The result was a deal of 5,359,950 pounds (47,275,367 yuan).Made during the Ottoman Empire conqueror Muhammad II (about 1480, equivalent to about 16 years of Gengzi in the Ming Dynasty), Turkey had imported Chinese Yuan and Ming blue and white porcelain for many years.As a result, Iznik glazed pottery is deeply influenced by Islamic metal ware and Chinese Yuan and Ming Dynasty blue-and-white flowers.Especially in Turkey, the Iznik glazed pottery appeared in the second half of the 15th century to the end of the 17th century, and this large plate, Iznik glazed pottery early fruit is one of the only five green large plate (the other four are hidden in the French Louvre Museum, Many museums around the world can see mid-to late-Iznik tiles.The glazed pottery of this period shows the early stage of kiln fire control, the color is full-bodied hair sink;And the use of mature bright cobalt blue material, not until two hundred years later.Therefore, Turkey’s Istanbul Topkapa Palace Museum has a large collection of Yuan, Ming-hua, but rarely Iznik glazed pottery green plate.This large market was once the chairman of the alexandrian archaeological association of egypt, businessmen and collectors marx durban old collection, so there is a “durban pan” name.In view of this, it further explains that the world’s recognition and appreciation of ancient blue and white utensils.However, in the years after the Warring States Period, the use of this material has not received the attention and inheritance of posterity.Only after the trade between Tang Dynasty and Western Asia did cobalt material be brought into China, and then there appeared the colorful and romantic three-color Tang Dynasty.The appearance of blue and white (cobalt blue) in these three colors had a direct influence on the blue and white porcelain of Gong Xian Kiln in Tang Dynasty, and it also became the origin of Chinese blue and white porcelain.

1. Definition of Blue and White Porcelain

Blue-and-white porcelain refers to a type of porcelain with white and blue flowers.Foreigners call it: “Blue and white”;The Japanese say, “Dyeing and Payment”.It is a kind of under-glaze color painting, with cobalt oxide containing minerals as colorant, directly on the porcelain billet painting decoration, and then covered with a layer of transparent glaze, placed in the kiln, after 1300 ° c of high-temperature reduction flame roasting made.

According to the above characteristics, the process of making blue-and-white porcelain can be summarized as follows:

1. Use cobalt earth as a colorant for green materials.

2. Drawn directly with green material on green billet.

3. Cover the painted porcelain with a transparent glaze.

4. After entering the kiln, a high temperature of 1300 ° c is used to burn in the atmosphere of reducing flame.

2. Characteristics of Blue and White Porcelain

Our country’s blue-and-white porcelain, unique in the history of Chinese ceramics, enjoys a high reputation in the world, has a “national porcelain” name.The blue-and-white porcelain has been cherished and loved by the world since its appearance. It is determined by its unique characteristics:

L, the tone elegant, elegant and generous, pleasing to the eye.

2. The painting content combines with the traditional Chinese calligraphy and painting art to create blue-and-white porcelain paintings with Chinese characteristics.

3. The glaze is bright and clean with a fine texture;And lead-free poison, pollution-free, green environmental protection, in line with the health requirements.

4, Under-glaze color painting long-term, not easy to wear, not corroded, will not fade.

5. Production procedures, relatively simple, one-time firing, low-cost.

3. Blue and white materials can be divided into three categories according to their chemical composition

1. Low manganese-Tang Qinghua is of this class.

Characteristics of chemical composition:

(1) The ratio of manganese to cobalt is low, and the content of blue and white flowers is 0.22, so the color of blue and white flowers is bright.

(2) Copper Containing

(3) Free of arsenic, zinc and nickel.

2. The high manganese class _ Song Qing Hua, Yuan Qing Hua part, Ming Dynasty middle and late period and Qing Dynasty all blue and white all belong to this kind.

Variety: equal green, stone green, Hui green, Zhejiang material, Zhu Ming material, and so on.

Characteristics of chemical composition;

(1) Manganese and cobalt are relatively high.

(2) Iron-cobalt ratio is high and low.

(3) Free of copper, arsenic, zinc, and sometimes a small amount of nickel.

3. Low-manganese high-iron type _ Yuan Dynasty and Ming Dynasty Hongwu, Yongle, Xuande and Chenghua early “Su Ma Liqing” are of this kind.

Characteristics of chemical composition;

(1) The ratio of manganese to cobalt is low, and the blue and white flowers in early Ming Dynasty are 0.01 _ 0.06.

(2) The iron-cobalt ratio was high, and the blue and white flowers in early Ming Dynasty were 2.21 _ 3.02.As a result of above two reasons, so blue and white hair color than domestic materials bright, with “rust scar”, color appears to be heavy.

(3) containing arsenic.

(4) Copper free.

The biggest difference between domestic green material and imported green material is that there is high manganese content in cobalt soil and high iron content in imported green material.High content of manganese of domestic green material, if used less, it will be fired after a blue with purple effect, suitable for marking and sketch graphics, if used more, or similar freehand ink, appear gray and dull.And the source of imported green materials are in the form of arsenate, such as: arsenate cobalt ore, this cobalt ore does not contain manganese, high iron content, so blue will be more pure, more dense;Iron molecules in the high temperature reduction, on the one hand will make the blue material appears black in the blue, but also reduce the glaze around the green material melting degree, so that contains more iron molecules in the place, there will be fainting phenomenon, so the small blue and white lines will appear not clear enough.However, this kind of faint and thick effect, actually has one kind of Chinese ink painting interest instead.