The most philatelically significant aspect of paper is watermarks. Watermarks are the pattern placed on the mat or roll on which the paper is produced. Both laid and wove paper can be watermarked. Watermarks were developed as a form of advertising for the papermaker. When held up to the light, the pattern that was placed on the papermaking mat becomes apparent because the paper is thinner where the pattern is. Stamp producers, in their zeal to foil counterfeiters, placed watermarks on the paper on which stamps were produced in hopes that this additional step would make counterfeiting even more difficult. Great Britain has almost always watermarked its stamps, beginning with a simple crown pattern. The United States did not initially feel the need to order stamps on watermarked paper, and only began watermarking its stamps in 1895 when the Bureau of Engraving and Printing took over from private contractors.
Two United States watermark varieties were used; identical-looking stamps with different watermarks are treated by philatelists, both advanced and novice, as completely different items. The differences can mean thousands of dollars to the discriminating collector. An understanding of the techniques of watermarking, which will be thoroughly discussed in the next chapter, can be mastered by anyone with a modicum of patience.
It is doubtful whether watermarking ever acted as an effective anticounterfeiting tool for postage stamps, its original intention. The United States ended watermarking on postage stamps in 1918. Canada never regularly watermarked its postage stamps.
Two interesting types of nonofficial watermarks occur on postage stamps, adding spice to the hobby and value to those particular stamps on which they are found. Stitch watermarks look like a series of tightly made stitch marks on the fiber of the paper. They are caused when the fiber mat (on which the wove paper is made) tears and is repaired by stitching with thread.Papermaker watermarks are one of a papermaker’s ways of advertising. They generally occur on stamps on which the government did not order a specific watermark, or did not use rigid specifications as to what paper it accepted.
Papermaker watermarks are typically broad watermarks extending fully across the sheet, whereby only a fragment of one of the letters of the name shows on any particular stamp. Indeed, because the records of the paper suppliers are often unavailable and because specimens with papermaker watermarks are scarce, students of papermaker watermarks frequently can only assert that a particular stamp is known with a papermaker watermark, but are unable to identify the particular watermark. Unfortunately, the study of these two types of watermarks has fallen out of vogue in recent years. The best collection was sold in London in the 1940s. The major United States stamp catalogue, Scott, dropped many of them from its listing in the 1950s. Still, they do have value, and if you can pick up a stitch or papermaker watermark from your stamp dealer for the same price as a regular stamp, you can consider your purchase profitable.