Printed Promotional Mugs
As a ubiquitous desktop item, the mug is often used as an object of art or advertisement; some mugs are rather decorations than drinking vessels. Carving had been traditionally applied to mugs in the ancient times. Deforming a mug into an unusual shape is sometimes used. However, the most popular decoration technique nowadays is printing on mugs, which is usually performed as follows: Ceramic powder is mixed with dyes of chosen color and a plasticizer. Then it is printed on a gelatin-coated paper using a traditional screen-printing technique, which applies the mixture through a fine woven mesh, which is stretched on a frame and has a mask of desired shape. This technique produces a thin homogeneous coating; however, if smoothness is not required, the ceramic mixture is painted directly with a brush. Another, more complex alternative is to coat the paper with a photographic emulsion, photoprint the image and then cure the emulsion with ultraviolet light.
After drying, the printed paper, called a litho, can be stored indefinitely. When a litho is applied to the mug, it is first softened in warm water. This detaches the gelatin cover, with the printed image, from the paper; this cover is then transferred to the mug. The mug is then fired around 700–750°C, which softens the top surface of the glaze, thereby embedding the image into it.