produced by means of a design on the dandy roll of
the papermaking machine that is intaglio instead
of in relief, thus thickening the sheet at the
point of contact. It causes the watermark to
appear darker than the rest of the sheet, rather
than lighter, as is the case with the true
watermark. The earliest shade-craft watermark
(known as a "light-and-shade" watermark) was
produced by the Frenchman Jannot in about 1812.
His, of course, was not produced by a dandy roll.