One variety of inflated glass is known as mold-blown glass. Glassmakers create decorative vessels by blowing glass into a mold containing incised designs. They can use a single mold or a mold with several parts, one for each segment of the vessel.
Ancient molds were often made of bronze, clay, plaster, or stone. The earliest designers of glass molds were probably ceramists (potters) who had experience making molds for clay vessels.
Glassmakers decorate vessels using a variety of tools and techniques.
They use pincers and tongs to pinch, pull, and push hot glass into different shapes and patterns. They wind glass around a vessel to create snakelike patterns and add handles, rims, and feet.
To create a special kind of decorative glass known as splashware, glassmakers roll a vessel in multicolored glass chips, reheat the vessel, and then further inflate it to stretch the chips across the surface to look like splashes of color.
Glassmakers also ornament glass vessels after they cool by painting them or using a lathe and cutting wheel to form decorative patterns. Painted glass vessels are rare, and none have survived with their pigments intact.