The sheen of a purple Clay Teapot, also known as “Water color,” can appear either lustrous or dull. What causes this difference? Is it the clay material, the craftsmanship, or something else?…
We see various colorful substances with our eyes because these substances reflect light. The less reflective they are, the darker they appear. If they don't reflect any light at all, we wouldn't be able to see them even in sunlight, which is the principle behind invisibility.
After being fired to crystallization, a purple clay teapot forms a sandy texture due to surface contraction. Most of the light is absorbed by this texture, which is why new purple clay Teapots appear relatively dim compared to other objects. Only a small portion of the light is reflected from the crystal surfaces, allowing us to perceive their presence.
When a purple clay teapot has been maintained and polished for some time, it reflects light from the Tea and oils that have been absorbed into the varying depths of its textured surface. This greatly increases the density of the reflective points, and since the light is refracted from different depths, it appears to have depth, creating an effect similar to a luminous cloud. Additionally, the light scattered from the crystal points resembles a mist.
Therefore, authentic purple clay teapots do not look overly bright, nor do they glare under strong light; instead, they give off a warm and smooth appearance.
While assessing the sheen may seem straightforward, it requires practice. A purple clay teapot with good sheen must be made from pure and high-quality clay material, crafted with excellent skill, and fired at the correct temperature:
1. The clay material must be pure and of high quality. Only clay with high sand particle purity allows the sand particles to become fixed, making the burnishing process effective (if it's non-local clay, applying pressure during burnishing will cause the sand particles to sink in and the powdered clay to rise).
The sand particles must be uniformly consistent. If there are many impurities or uneven petrification, the different firing temperatures and resulting colors make it difficult to achieve a lustrous sheen. Therefore, a teapot with a lustrous sheen is definitely made from high-quality clay.
2. It must be crafted with exceptional skill. Without skilled burnishing to smooth out the sand particles and clean the lipid clay, it would be impossible to achieve a lustrous sheen. Even the best clay would result in a mud-like color without burnishing. Thus, a teapot with a lustrous sheen is certainly well-crafted.
3. The teapot must be fully fired and vitrified at the right temperature. Purple clay belongs to the kaolinite-quartz-mica type and possesses an optimal particle composition. A purple clay teapot that hasn't been fired to crystallization cannot have a lustrous sheen.