Glazing pottery or ceramics is a delicate art that requires careful consideration of various factors to achieve the desired results. One common practice that you may have noticed is that artisans often leave the bottom of their pieces unglazed. While it might seem counterintuitive, there are valid reasons behind this approach.
1. Preventing Sticking
When clay is fired, it undergoes significant changes in its physical properties. Glaze, when heated, transforms into a glassy surface. If the glaze is applied to the bottom of a piece, it can melt and fuse with the kiln shelf during firing. This can lead to the piece becoming permanently stuck to the shelf, causing damage to both the artwork and the kiln.
2. Stability During Firing
Applying glaze to the bottom of a piece can also affect its stability during firing. Glaze tends to shrink as it dries and then expands again as it melts in the kiln. This expansion and contraction can cause the piece to warp or even crack if the glaze adheres tightly to the bottom, preventing it from moving slightly during firing.
3. Aesthetic Considerations
Leaving the bottom of a piece unglazed is often a deliberate aesthetic choice. The contrast between the unglazed bottom and the glazed surfaces can enhance the visual appeal of the artwork. It also allows the natural color and texture of the clay to shine through, adding to the overall beauty of the piece.
4. Functional Reasons
In functional pottery, such as cups, bowls, and plates, leaving the bottom unglazed provides a practical benefit. Unglazed bottoms offer better traction and stability when the piece is placed on a surface. This can help prevent slips and spills, making the piece more user-friendly.
Conclusion
Not glazing the bottom of pottery or ceramics is a carefully considered practice that takes into account both functional and aesthetic aspects. By leaving the bottom unglazed, artisans ensure that their pieces remain stable during firing, prevent sticking to kiln shelves, and enhance the overall visual appeal of their creations. This thoughtful approach showcases the mastery and attention to detail that go into the art of pottery.