Editing Watermark

{{Short description|Identification on paper to prevent counterfeiting}}
{{about|physical watermarks|digital watermarks|Digital watermarking|other uses|Watermark (disambiguation)}}
{{more citations needed|date=November 2013}}
A '''watermark''' is an identifying image or pattern in [[paper]] that appears as various shades of lightness/darkness when viewed by transmitted light (or when viewed by reflected light, atop a dark background), caused by thickness or density variations in the paper.<ref>{{cite book |last1= Biermann|first1= Christopher J. |title= Handbook of Pulping and Papermaking |url= https://archive.org/details/handbookpulpingp00bier|url-access= registration|edition= 2 |year=1996 |publisher= Academic Press|location= San Diego, California, USA|isbn= 0-12-097362-6|page=[https://archive.org/details/handbookpulpingp00bier/page/n187 171] |chapter= 7}}</ref>
Watermarks have been used on [[postage stamp]]s, [[currency]], and other government documents to discourage [[counterfeit]]ing. There are two main ways of producing watermarks in paper; the ''dandy roll process'', and the more complex ''cylinder mould process''.

Watermarks vary greatly in their visibility; while some are obvious on casual inspection, others require some study to pick out. Various aids have been developed, such as ''watermark fluid'' that wets the paper without damaging it.  A watermark is very useful in the [[questioned document examination|examination]] of paper because it can be used for dating documents and artworks, identifying sizes, mill trademarks and locations, and determining the quality of a sheet of paper. The word is also used for [[Digital watermarking|digital practices that share similarities]] with physical watermarks. In one case, overprint on computer-printed output may be used to identify output from an unlicensed [[Trialware|trial version of a program]]. In another instance, identifying codes can be encoded as a [[digital watermark]] for a [[music]], [[video]], [[picture]], or other [[computer file|file]]. Or an artist adding their identifying digital Signature, graphic, logo in their [[Digital art|digital artworks]] as an identifier or anti-counterfeit measure .

== History ==
Watermarks were first introduced in [[Fabriano]], Italy, in 1282.<ref name="meggs58">{{Cite book | last = Meggs | first = Philip B. | author-link = Philip B. Meggs | title = A History of Graphic Design | publisher = John Wiley & Sons, Inc. | year = 1998 | edition = Third | pages = 58 | isbn = 978-0-471-29198-5}}</ref>  At the time, watermarks were created by changing the thickness of paper during a stage in the manufacturing process when it was still wet.

== Processes ==

=== Dandy roll process ===
[[File:Dandy Roll.png|thumb|right|A perspective view of a dandy roll in accordance with the invention of a conventional paper-making machine incorporating watermarks into the paper]]
Traditionally, a watermark was made by impressing a water-coated metal stamp onto the [[paper]] during manufacturing. The invention of the dandy roll in 1826 by John Marshall revolutionised the watermark process and made it easier for producers to watermark their paper.

The ''dandy roll'' is a light roller covered by material similar to [[window screen]] that is embossed with a pattern. Faint lines are made by ''laid wires'' that run parallel to the axis of the dandy roll, and the bold lines are made by ''chain wires'' that run around the circumference to secure the laid wires to the roll from the outside. Because the chain wires are located on the outside of the laid wires, they have a greater influence on the impression in the pulp, hence their bolder appearance than the laid wire lines.

This embossing is transferred to the [[Wood pulp|pulp]] [[fibre]]s, compressing and reducing their thickness in that area. Because the patterned portion of the [[page (paper)|page]] is thinner, it transmits more [[light]] through and therefore has a lighter appearance than the surrounding paper. If these lines are distinct and parallel, and/or there is a watermark, then the paper is termed ''laid paper''. If the lines appear as a [[mesh]] or are indiscernible, and/or there is no watermark, then it is called ''wove paper''. This method is called ''line drawing watermarks.''

=== Cylinder mould process ===
Another type of watermark is called the ''cylinder mould watermark''. It is a shaded watermark first used in 1848 that incorporates tonal depth and creates a [[greyscale]] image. Instead of using a wire covering for the dandy roll, the shaded watermark is created by areas of relief on the roll's own surface. Once dry, the paper may then be rolled again to produce a watermark of even thickness but with varying density. The resulting watermark is generally much clearer and more detailed than those made by the Dandy Roll process, and as such, Cylinder Mould Watermark Paper is the preferred type of watermarked paper for banknotes, passports, motor vehicle titles, and other documents where it is an important anti-counterfeiting measure.

== On postage stamps ==
{{See also|Postage stamp paper}}
[[File:Watermark Crown CA.jpg|thumbnail|right|The ''Crown CA'' watermark found on many British Commonwealth stamps (seen from the reverse)]]
[[File:FawnEnvelope1883Plimpton.jpg|right|thumb|A US postal stationery envelope from 1883 showing a clear watermark on [[laid paper]]]]

In [[philately]], the watermark is a key feature of a stamp, and often constitutes the difference between a common and a rare stamp.  Collectors who encounter two otherwise identical stamps with different watermarks consider each stamp to be a separate identifiable issue.<ref>{{cite web|url=http://www.linns.com/howto/refresher/watermark_20051010/refreshercourse.aspx|title=Miller, Rick; ''Stamp identification often lurks in watermark'' in Linns.com Refresher Course section|access-date=2010-12-08|archive-date=2010-06-16|archive-url=https://web.archive.org/web/20100616075435/http://www.linns.com/howto/refresher/watermark_20051010/refreshercourse.aspx|url-status=dead}}</ref>  The "classic" stamp watermark is a small crown or other national symbol, appearing either once on each stamp or a continuous pattern. Watermarks were nearly universal on stamps in the 19th and early 20th centuries, but generally fell out of use, but some countries continue to use them.<ref name=Baadke>{{cite web |url=https://www.linns.com/news/postal-updates-page/stamp-collecting-basics/1998/october/how-to-identify-a-stamp-by-its-watermark-.html|title=Baadke, Michael; ''How to identify a stamp by its watermark'' in Linns.com Refresher Course section }}</ref>

Some types of [[Embossing (paper)|embossing]], such as that used to make the "cross on oval" design on early stamps of [[Switzerland]], resemble a watermark in that the paper is thinner, but can be distinguished by having sharper edges than is usual for a normal watermark.  Stamp paper watermarks also show various designs, letters, numbers and pictorial elements.

The process of bringing out the stamp watermark is fairly simple.  Sometimes a watermark in stamp paper can be seen just by looking at the unprinted back side of a stamp.  More often, the collector must use a few basic items to get a good look at the watermark.  For example, watermark fluid may be applied to the back of a stamp to temporarily reveal the watermark.<ref name=Baadke />

Even using the simple watermarking method described, it can be difficult to distinguish some watermarks.  Watermarks on stamps printed in yellow and orange can be particularly difficult to see.  A few mechanical devices are also used by collectors to detect watermarks on stamps such as the Morley-Bright watermark detector and the more expensive [[Safe Signoscope]].<ref>{{Cite web |title=Signoscope Watermark Detector T3 |url=https://www.safepub.com/product/signoscope-watermark-detector-t3/?srsltid=AfmBOooCj0HG3DezFBXSClHwFT_Nj7H-2pYKqWT_fZjJpVOJHjjUNKX7 |access-date=2024-09-30 |website=SAFE Collecting Supplies |language=en-US}}</ref> Such devices can be very useful for they can be used without the application of watermark fluid and also allow the collector to look at the watermark for a longer period of time to more easily detect the watermark.

== See also ==
* [[Allan H. Stevenson]]
* [[Chip art]]
* [[Digital watermarking]]
* [[Huaya]]
* [[Overprinting]]
* [[Overprint]]
* [[Seals in the Sinosphere]]
* [[Thomas Harry Saunders]]

== References ==
{{Reflist}}

==Further reading==
* Buxton, B.H. ''The Buxton Encyclopedia of Watermarks''. Tappan, N.Y.: Buxton Stamp Co., 1977 114p.
* Felix, Ervin J. ''The Stamp Collector's Guidebook of Worldwide Watermarks and Perforations, from 1840 to date''. Racine, WI.: Whitman Publishing Co., 1966 256p.
* Repeta, Louis E. ''Watermarks In Postage Stamp Paper: a comprehensive look at a key stamp element''. Reprinted in 1999 from ''[[The American Philatelist]]'' (February 1987). 27p.

== External links ==
{{Wiktionary|Watermark}}
{{Commons category|Watermarks}}
* [https://www.wzma.at WZMA - Watermarks of the Middle Ages]
* [https://memoryofpaper.eu/briquet/BR.php Briquet online (in French)]
* [https://www.piccard-online.de/struktur.php?anzeigeKlassi=&klassi=&sprache=en Piccard online (English)]
* [http://www.wm-portal.net/niki/index.php Watermark Database of the Dutch University Institute for Art History]
* [https://www.memoryofpaper.eu Bernstein - The Memory of Paper, Portal to 50 Watermark Databases]
* [http://www.watermarks.info/catalogi.htm Watermarks 1850-date]
* [http://www.hobbizine.com/page0023.html ''Finding Watermarks on Stamps'']: Hobbizine article
* [https://www.gravell.org/ Thomas L. Gravell Watermark Archive]
* [https://library.udel.edu/static/purl.php?mss0339 Thomas Gravell watermark collection], Special Collections, University of Delaware Library, Newark, Delaware.
* [http://abacus.bates.edu/wmarchive Archive of Papers and Watermarks in Greek Manuscripts]
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[[Category:Philatelic terminology]]
[[Category:Money forgery]]
[[Category:Papermaking]]
[[Category:Watermarking|*]]
[[Category:Stationery]]
[[Category:Banknotes]]
[[Category:Italian inventions]]

[[io:Filigrano]]