The process of dampening paper before printing.
Wetting down was necessary in the early days of
printing because of the non-uniformity of the
height of the type used, and because type was used
longer and. therefore, wore down more. In
addition, the early hand-operated presses were not
as powerful as later presses. Slightly dampened
paper takes ink more readily than dry paper. and
does not require as much pressure to make the
impression on the softened surface of the paper.
The impression, however. makes a thicker line and
may also show on the other side of the sheet.
Wetting down also often resulted in uneven
stretching of the paper fibers during impression,
causing the book to be thicker in the printed area
than in the margins. See also: CONVEX COVERS .