SHEET HAVING A MULTI-TONE WATERMARK, METHOD FOR MANUFACTURING A PART FOR FORMING A MULTI-TONE WATERMARK, PART FOR FORMING A MULTI-TONE WATERMARK, AND USE OF SAID PART FOR FORMING A MULTI-TONE WATERMARK

摘要

The present invention relates to the field of paper and relates to a sheet including a high-definition high-contrast multitone watermark having areas of pronounced brightness. Such watermark is particularly obtained by means of a part (4) including a surface (5) having a raised area and perforations (6). The perforations (6) are such that making the cross-section thereof, at a given distance from the draining surface, directly depends on said distance. The present invention also relates to the method for manufacturing said part that is used for forming one such watermark, to the part itself, and to the use of said part when forming a watermark.