Decalcomania or Decal for short is the process of transferring pictures or printed designs from specially prepared paper to various materials, such as porcelain.
Decalcomanias or Decals are prints on which the design is printeded with oil based glaze colors on a gelatin covered paper and covered with a protective varnish. After the paper is soaked in water the decoration can be slid over to the glazed porcelain surface and fired to permanently sticking onto the glaze. Unlike earlier techniques that could be applied under the glaze as well as on top of it, decalcomanias were applied exclusively over the glaze.
With this method the decorations could be as detailed and multi-coloured as the printers could make them. Single or multicolored overglaze images can be printed, hand painted or both onto the decal paper. This type of decoration still occurs on porcelain with decorative purpose only since it does not wear as well as (dish washer safe) underglaze decorations. Even computer aided designs and laser prints can be used.
Around 1875 decals or decalcomania pictures came into use in Europe for decorating ceramics. In China decalcomania onglaze enamel decorations occured on porcelain (Weimin factory, Jingdezhen) as late as early 1990s.
In Europe during the 19th century, decalcomania pictures appears to have been bought from specialised firms, why similar designs could be found on wares from different companies. In Germany decals could be supplied by firms such as Zierdruckanstalt Lindenruh in Lindenruh-Glogau, E. Wunderlich in Waldenburg-Altwasser and Buntdruckerei für Keramik Carl Nitzke in Leipzig.