Back (printing technique)

Spine describes the narrowing of the engraving in a rotary printing process to compensate for the shrinkage of the paper web.

Solvent and water are removed from the paper web during drying. Therefore, the paper shrinks and becomes narrower. In order to register to avoid -Differenzen between the individual colors, the engraving is compressed parallel to the cylinder axis, and thus adapted to the narrower paper web. This process is called back. The first color remains unchanged. The following colors are moved inwards by about 0.4 mm, 0.6 mm and 0.7 mm.