What is Zisha reduction firing?
It is generally acknowledged that the original purple sand is rich in iron. When the purple sand is put into the kiln for firing, it is actually a series of reactions.
The reason why the purple sand is red is partly because it is rich in iron ions. When firing, only the surface of the pot can contact the air, so an oxidation reaction will occur, and the iron will be oxidized into ferric oxide, which appears red.
The inner layer of the teapot cannot be exposed to oxygen, and during the firing process, the iron-containing components inside can only be reduced to black iron, so it becomes gray-black.
This is the principle of reduction firing. When the temperature in the kiln reaches a certain level, the oxygen in the kiln is reduced to artificially turn it into an oxygen-deficient firing environment. The remaining small amount of oxygen will continue to burn and be consumed.
Due to the large amount of charcoal ash produced during the wood-burning process, it cannot produce an oxidation reaction in the local environment to form a reducing atmosphere. The direct contact between the green body and the charcoal and the flame causes a local firing temperature difference and a pressure difference in the kiln. In this mixed atmosphere, the green body is completely reduced, and the iron oxide in the green body is reduced to iron oxide.
The purpose of restorative firing of purple clay is to turn "defects" into magic, that is, to pursue the artistic effect of restorative firing of purple clay pottery. The process of making a purple clay pot is the communication between hands and clay, the dance between clay and fire. People only know the exquisite pottery craftsmanship of purple clay artists, but they don't know that the firing process is also extremely important, which is the finishing touch.
Since the development of purple sand craftsmanship, more and more artists have flexibly used purple sand reduction firing to produce unique purple sand artistic effects.
Reduction firing was a skill used to make up for defects in the past, but through the vision and craftsmanship of modern pot-making artists, the most essential and original unique charm of purple sand has been recognized and loved by more people. This is also the unique charm of handmade products that can only be seen but not foreseen.
When artists accidentally realized the kiln change phenomenon during the firing process, they tried to try and master this elusive special skill.
Using different clays, different temperature differences, and different techniques, the luster presented by reduction firing varies from blue-gray, dark dark green, and black jade, with a charming metallic texture. This is precisely due to the innovative and exploratory spirit of the artists, thus adding a new artistic treasure to the firing field. I believe it will definitely bring a new atmosphere to the purple sand art field.
