Copper and iron often play a key role in the firing of porcelain, especially in the process of glaze color development.
But in malachite green glazed porcelain, copper is the key, not iron.
Malachite green glazes in ancient China generally contain only a small amount of iron oxide, and the content is less than 1%, which has little effect on the glaze color.
Modern research has proven that the malachite green glaze fired in the north before the Qing Dynasty also contained a large amount of lead and a small amount of the opacifying agent tin dioxide.
The results of chemical analysis show that the appearance of tin dioxide is related to copper.
In malachite green glazes before the Qing Dynasty, if the copper content in the glaze was high, tin would generally appear, and vice versa.
This shows that tin may have been brought in as an ingredient from the copper oxide slag produced when smelting bronze, rather than being added intentionally.
Bronze is a copper-tin-lead alloy. During the Qing Dynasty, bronze production had been replaced by brass and red copper. The slag produced during the smelting of brass and red copper was mainly copper oxide and did not contain tin, so the results of chemical analysis did not find tin.
As mentioned earlier, malachite green glaze is sometimes a bit bluish. It is generally believed that the blue color is caused by cobalt oxide.
However, the results of chemical analysis show that, with the exception of a few purple-blue fahuacai fired early in the north, which contain about 0.6% cobalt oxide, most peacock blues do not contain cobalt.
In addition to cobalt oxide, the early-fired purple-blue fahuacai also contained a small amount of manganese oxide, which was caused by the use of cobalt earth ore as the source of cobalt oxide.
Malachite green glaze is colored by divalent copper ions and must be fired in an oxidizing flame. The firing temperature is 950~1000℃.
After researching and understanding these, at least with malachite green glaze and malachite blue glaze, there is no need to worry about unsuccessful firing.
What's more, Chen Wenzhe also watched the entire firing process of malachite green glaze official kiln porcelain in the Qing Dynasty.
Knowing how to mix it, there is no way to say what the final effect will be due to the different raw ore materials that can be used.
Also, the effects brought by the final kiln firing process are definitely different.
So, I still have to try burning it this time.
To test burn, you need to do more experiments first, so that you can know what kind of effect you will get under various circumstances.
Do more, not just casually. This time Chen Wenzhe plans to do the same as before, and imitate all the best ancient porcelain.
As for peacock blue glazed porcelain, the best ones must have been fired during the Ming and Qing dynasties.
This kind of glaze was already produced in the Xuande period of the Ming Dynasty. Malachite green was more famous in the Zhengde period, and the firing of this glaze was very popular in the Kangxi period of the Qing Dynasty.
Guangxu Chao green glazes enjoyed a high reputation in the late Qing Dynasty, including malachite green, melon skin green, turquoise green, etc.
Among them, the types of malachite green glazed vessels are mostly study utensils such as cone-handled vases, skimming vases, Guanyin vases, celestial sphere vases and washing vases, as well as lions, parrots and other ornaments.
Chen Wenzhe can make some of these, especially the ornaments. It turns out that Chen Wenzhe has not made many.
It's just that he used to learn glass-type ornaments, but now he makes porcelain ornaments, or malachite green glazed porcelain ornaments, and it doesn't seem to be difficult.
Regardless of whether it is difficult or not, when making any new type of porcelain, it is best to start with a simple shape.
After all, it is a test firing to see what the final color will be, so in order to pursue speed at the beginning, it is best to make dishes.
Of course, bowls and dishes were not made casually. Chen Wenzhe was the first to imitate several malachite green glazed bowls from the Zhengde period of the Ming Dynasty.
As for why, could he still say that the boy Zhang Gu was making bowls too fast? As long as he had some ideas, he would start researching on providing utensil embryos.
Since there is a prototype on site, why would he go to the trouble of making it himself?
The malachite green glaze bowl must be a low-temperature glaze that is emerald green and translucent, resembling peacock feathers.
Because copper is used as the coloring agent, the glaze color can be dark or light.
Here, you need to control it yourself, which is also the purpose of test burning.
Pick up a bowl and touch it with your fingers. The wall is smooth and even, the texture is hard, and the crotch is well done.
This kind of peacock green glaze bowl is easy to make. After all, it has a lip, curved walls, thin bottom, and rounded feet, and there is no need to write a payment.
The inner wall of the bowl and the ring foot are glazed with blue-white glaze, and the outer wall is glazed with malachite green glaze. Near the foot, there is a hidden lotus petal pattern.
Although this kind of bowl is not signed, its typical Zhengde palace bowl shape and the light green and white glaze on the base of the bowl all indicate that it is a Zhengde official kiln vessel.
The firing of malachite green glaze reached its peak during the Zhengde period of the Ming Dynasty. Therefore, if the imitation firing is to be successful, the color of the fired glaze must be green and bright.
These malachite green glaze bowls are not small in size, with a height of 6.6cm, a diameter of 16.2cm, and a foot diameter of 6.5cm.
It went smoothly, and Chen Wenzhe made all the glaze recipes he could think of.
One bowl and one glaze recipe. Anyway, it can be made quickly. Once it dries a little, it can be fired in the kiln. The result will be completely clear by the next morning.
After the firing results of this batch of bowls come out, he will fine-tune the formula based on inherited experience and get what he wants.
In this way, he originally planned to make only three malachite green glazed bowls, but in the end he made more than a dozen.
These bowls use different proportions of glazes, so when fired according to the method of malachite green glazed porcelain, what kind of green color will appear in the end can only be known after the firing is completed.
After making these bowls, Chen Wenzhe made the plates directly without thinking too much.
The small plates are simpler than the plates, but Chen Wenzhe now wants to increase the difficulty and adjust the glaze ratio relatively large, so this time he made light green glaze cups and saucers with dark flower and chi pattern.
Although copper is still used as the coloring agent this time, the final fired result is not necessarily light or rich in color.
It's not even necessarily green, maybe it's red glazed porcelain.
The glaze formula is not accurate enough. It may be a copper red glaze, a purple glaze, or even a celadon glaze. This depends on the temperature control inside the kiln.
No matter what, he couldn't get the malachite green glaze accurately, so he simply imitated the light green glaze cup and saucer with dark flower and chi pattern from the Kangxi period of the Qing Dynasty.
In the end, if the color is suitable, it will be malachite green glaze. If it is not suitable and the color is too light, it will be light green glaze.
If other colors appear, it means the firing failed.
The price of failure is nothing more than a cup, a butterfly, or at most a set of cups and saucers.
Because this is a set of porcelain, it is called a cup and saucer. The cup and saucer are combined into one set.
The cup height is 3.5 cm, the diameter is 5.7 cm, and the foot diameter is 2.4 cm;
The height of the dish is 1.6 cm, the diameter is 12.7 cm, and the full diameter is 10 cm.
The appliances are not big or complex, and they are easy to make.
The mouth of the cup is slightly tilted, the belly is deep, the feet are circled, and the halberd ears are placed symmetrically on both sides.
Apply white glaze on the inside and light green glaze on the outside.
Four chi tigers are secretly engraved on the outer wall, and the outer bottom is embossed with the blue and white "Kangxi Year of the Qing Dynasty" double-line six-character regular script inscription.
The dish has a skimmed mouth, a shallow arc wall, and a circle foot.
There is a protrusion on the inner bottom of the saucer, which can catch the cup foot when placing the cup. The center of the saucer is secretly marked with two dragon patterns.
The inside of the foot is glazed with white glaze, and the outer sole is also signed with the blue and white "Kangxi Year of the Qing Dynasty" double-line six-character regular script.