Data and the protection of one’s identity, assets and confidential material are an ever-increasing concern in an age where the breach of security is becoming commonplace. The importanceof staying one step ahead in protecting one’s image and information is critical, and it has never been easier to manipulate due to ever-changing technology and applications.
In the realm of printed material, there are a variety of precautions that can be taken to protect documentation, and it is essential to pursue security with a multi-layered approach, implementing numerous measures to authenticate paperwork.
Watermarking is one of the methods used in document security. With a new breakthrough in technology, it is more beneficial than ever to use. Banknotes, and many federal or state-issued photo IDs such as a driver’s license or passport, incorporate watermarks. The advantage of the new system for producing security marks makes it possible to mark synthetic papers (micro-porous structures), opening a new realm of possibilities.
Historically, security marks—also known as watermarks—have been developed for the protection of documents as an aid to counterfeit prevention.
Watermarked images are usually invisible or difficult to see, only easily viewed when illuminated from behind a document. In the 17th and 18th century, European paper was made by hand by dipping wooden framed metal screens with cellulose fibers into warm water, which would then naturally mat together, and wire designs were then sewn into the paper to create watermarks. Whimsical shapes, such as unicorns, lions and crowns would often be incorporated, and are believed to have been the papermaker’s trademark, also indicating the size and quality of paper. Some watermarks were used as symbols of secret brotherhoods to identify members, or as a marketing tool to promote the exceptional artisanship of a workshop.
There are three primary ways that paper is watermarked today. The first incorporates a Fourdrinier, or true watermark, which is made during the paper manufacturing process. Varying degrees of pressure are applied by a dandy roll that contains the image to paper that is still wet. Then, when the paper is impressed in select areas of varying thickness, the watermark will appear when illuminated from the back. The thicker layers of paper block and absorb light, appearing darker in color, while subsequently thinner portions let light through and appear lighter in color.
Another type of watermark is the cylinder mold waterma
rk. First used in 1848, it incorporates depth with a shaded, grey-scale image. Areas of relief on the roll’s outer surface cause the shading. Once dry, paper is rolled to produce a security mark of varying density and even thickness, which appears much clearer and more detailed than that using the dandy roll process. This is often used in banknotes, passports, motor vehicles titles and other documents where anti-counterfeiting measures are taken.
The third type of mark is an artificial, or pseudo simulated watermark created by printing an image using an opaque, white ink, transparent ink or using varnish. Unlike the watermarks produced by the other two processes, this watermark can only be seen from one side of the paper when viewed at an angle with reflected light. It is not visible when illuminated from the back of a document.
The methods described are all satisfactory methods used with regular paper (i.e. cellulose pulp fibers pressed into a sheet), but these three watermarking techniques have not been successfully applied to synthetic paper (i.e. hydrophilic, polymeric, micro-porous structures having a multitude of pores). Synthetic paper is commonly used for secure documents given its remarkable durability and difficulty to tear. A variety of hydrophilic, micro-porous and polymeric structures could be used as synthetic paper, including: polyesters, polyvinyl halides, polyolefins and acrylics with micro-voided structure. Teslin, from PPG Industries for example, is an ideal synthetic paper for incorporating the use of new watermarking technology.
With new laser technology, synthetic paper also can be watermarked using 
either a dry process or a wet process. This method is performed by deforming select portions of the micro-porous structure in a pattern corresponding to the mark and changing its light transmission characteristics. The laser beam’s radiant energy distorts the synthetic paper pores. With careful selection of laser parameters, such as wavelength, frequency, pulse duration and power level, this selective distortion could be done mostly sub-surface, affecting light transmission without significant change to the paper’s top layer. As with traditional watermarking, this technique provides low visibility under normal conditions, but will become highly visible when back illuminated.
The new laser watermarking technique adds options and functionality not previously possible. Security marks are a technical challenge to reproduce, copy or forge accurately, yet offer a simple means of verification through the use of back illumination with any available light source.
Here are some of the laser’s watermarking benefits:
- Time and money is saved on tooling changes. With this new process, changing a watermark is as simple as entering new text or a graphic into a laser-controlled program, which does not require special training to use. There is no longer a need to change tooling every time a watermark is altered. Saving time and energy, it streamlines watermarking with a more efficient procedure.
- Inexpensive and effortless customization per document. With ease, this new watermarking technology offers the ability to mark unique indicia per document, while still having the capability to do small print runs with the laser. For example, it would enable a covert watermarked serial number to match an overt printed serial number on the same paper, adding another layer of security on documentation. Providing a unique ID per document would have previously been costly to produce, but using this system, it can be done cheaply and efficiently.
- More secure data protection options are easy to incorporate. Laser watermarked QR codes, data matrix or barcodes could be made to read with special readers, or by use of a smartphone application, which would lead to relevant information about a source document at hand. Access to this information could help to authenticate the watermark by downloading relevant information about the document. At the same time it would automatically upload information about the use of the document preventing potential attempts to duplicate and reuse the code. In addition, scanning with a smartphone could also transfer geo-positioning information data and other revealing metadata, ultimately adding additional security and functionality to a document. An implementation of this technology could be, for example, at Border Control, where scanning and identification is regulated with utmost efficiency.
- High-resolution, high-contrast mark. Using a laser provides a sharp, high-contrast image, with the ability to incorporate intricate designs. Having a watermark brings an aesthetic, or decorative, element to a document, and it is useful for subtle corporate branding, as well as verification of paperwork. An Alphanumeric, logo, barcode or image could be produced with photographic quality. The semblance of a watermark created with a laser is superior to that produced using a traditional watermark making technics.
- The ability to watermark on synthetic paper, including post-production. To date, watermarking—which is currently being done on regular paper—is made during the paper manufacturing process. This new process offers the option of adding the watermark during post-production, which simplifies the manufacture and distribution process. In addition, watermarks can now be done on synthetic paper, which was previously difficult. Universally acknowledged as a more secure and longer lasting medium for documentation, the strength of synthetic paper makes it an ideal agent for highly secure documentation.
- Will survive the lamination process. Watermarking done by previous methods is not currently sustained on synthetic paper after the lamination process. However, in the case of laser watermarking synthetic papers, a major benefit is that the mark will continue to function after the lamination process. This makes it ideal for the protection of documents that requires to be laminated for durability.
An exciting leap forward in the already well-established realm of watermarking, the ability to laser watermark on newer, more secure substrates ultimately adds another layer of security and functionality. Preserving and improving upon the integrity of traditional watermarking methods, it will be interesting to see how the added functionality and flexibility of laser watermarking will be utilized in the future as an enabling technology.
David Benderly is founder, president and CEO of DBC Inc., the laser research and development subsidiary of PhotoScribe Technologies. A pioneer in the field of diamond marking systems, Benderly holds eight patents in diamond marking and is currently researching a solution for fingerprinting diamonds that will go beyond traditional plotting. Benderly’s work in the diamond field has had applications in medical, pharmaceutical, electronics and aerospace industries.
