Glassine is a smooth and glossy paper which is air-, water-, and grease-resistant. It is usually available in densities between 50–90 g/m2 (0.010–0.018 lb/sq ft). It is translucent unless dyes are added to the paper to color it or make it opaque. It is manufactured by supercalendering: after pressing and drying, the paper web is passed through a stack of alternating steel-covered and fiber-covered rolls called a supercalender at the end of the paper machine so that the paper fibers are oriented in the same direction.[citation needed]