Once a vessel is formed on the wheel or by hand, it enters the most volatile stage of the pottery process: drying. Clay contains a massive amount of physical water that must evaporate before the piece can ever see a kiln. As this water escapes, the clay particles draw closer together, causing the entire piece to shrink by up to 10% to 15%. If a piece dries unevenly—for instance, if the rim dries faster than the thick base—the resulting internal stress will cause the piece to warp or crack. Potters closely monitor these drying phases, waiting for the optimal state known as leather-hard. At this point, the clay has lost its stickiness and plasticity but retains enough moisture to be carved, handled, and trimmed. The leather-hard piece is flipped upside down onto the wheel to undergo trimming. Using sharp metal loop tools, the potter shaves away ribbon-like curls of excess clay from the bottom of the vessel. This process refines the outer profile, establishes uniform wall thickness, and carves a distinct "foot ring"—the raised rim on the base that allows the pot to sit flat and stable. After trimming, decorative handles are attached using a paste of liquid clay called slip. The piece is then left to dry completely until it becomes bone-dry or greenware. At this final pre-firing stage, the clay is entirely chalky, brittle, and fragile as glass. It must be handled with extreme care, as the slightest mishap can crumble days of meticulous work into dust.
