What is soft-paste porcelain? The term is sometimes thought to mean that this porcelain body is softer than true porcelain. However, it actually refers to the soft, or lower temperature, firing that is given this kind of porcelain. Soft-paste porcelain was developed in England before the secret of true porcelain was discovered there. It was made of a variety of materials, mainly white clay and ground glass. Glazes derived from lead were applied to soft-paste porcelain after it had been fired and required a second firing at lower temperatures. Pieces painted with enamel colors needed a third firing to sink the colors into the glaze.