By Zixiang Jin
A watermark is a pinpointing image that comes with variety of darkness or lightness when viewed by transmitted light. Government documents, including the field of currency and postage stamps are known to employ water mark in order to avoid forgery. Cylinder Mould and dandy roll processes are used in producing watermarks in paper. The new technique of laser’s watermarking has a wide range of benefits. They include secure data protection methods are easily incorporated, easy customization per document, high-contrast mark and time and money is saved on changing tools.
Various skills and techniques have been invented. Example include water fluid that water fluid that does not damage the paper even after wetting it. Examinations employs watermark. They are used in determining the quality of a sheet of paper, identifying sizes, dating, mill trademarks and locations. New technology breakthrough has made watermark a necessity. Watermark is incorporated in document security such as driver’s license, banknotes, passports and other state issued-photo IDs (Benderly, 2015).
Today, paper can be watermarked using three processes. One way is use of Fourdrinier which is made during paper manufacturing process. It is often referred to as a true watermark. Dandy roll applies varying degrees of pressure. The dandy roll contains the image to paper that is still wet. The paper is impressed in select areas of varying thickness making the watermark to appear when illuminated from the back. The thicker layers of paper block and absorb light (Benderly, 2015). This ensures the darker color. The thinner portions appear lighter in color because they let light to pass through them.
Artificial is another type of mark. It is created by printing an image using an opaque, transparent ink, white ink or using varnish. The process is quite unique because it can be seen from one side of the paper when viewed from an angle reflected with light. When illuminated from one side of document it is invisible.
Cylinder mould is also a common type of watermark. It includes depth with shaded, grey scale image. Shading is caused by areas of relief on the roll’s outer surface. Paper is rolled once it is dry to produce a security mark of varying thickness and density. This process appears more detailed and much clearer compared to using the dandy roll process. It is commonly used in motor vehicles titles and other documents where measures of anti-counterfeiting are taken.
The laser technology has made it possible to have made it possible for synthetic paper to be watermarked. The process used can either be wet or dry process. It is done by deforming the selected portions of the micro-porous structure in a pattern corresponding to the mark and changing its light transmission characteristics. The synthetic paper pores is distorted by radiant energy from the laser beam. Careful selection of laser parameters will help the paper’s top layer to remain the same. The technique under normal conditions provides low visibility. When illuminated it becomes highly visible.
David Benderly (2015) New watermarking techniques provides additional security benefits in Authenticating documentation. Photoscribe Technologies
Buxton B.H (1977) The buxton encyclopediaof watermarks. Tappan, New York.