Improvements in watermarking

A watermark formation element has an integrated body comprising a watermark forming surface, which has one or more watermark forming regions, and a drainage surface. The watermark formation element has a plurality of drainage channels 22 extending from watermark forming surface apertures 23 to drainage surface apertures 24. The watermark forming surface comprises a plurality of solid areas 28 between the drainage surface apertures. Some solid areas are larger than others and have an area of at least three times that of each of the drainage surface apertures 24. The solid areas may be planar rounded or stepped. The solid areas may cover some drainage channels 22 or may extend between the formation and drainage surfaces. The solid area may have a maximum dimension of 2mm. The element may be of layered construction and formed by 3D printing. The channels 22 may have a minimum cross-sectional area of 0.01mm2