Document Security - Between Lines

(document Security-Hanging By a Thread) The security of many securities and important documents is tied between the front lines such as banknotes, cheques, passports, vouchers and certificates. As early as in the late 1930s, there was a method of embedding security lines in the paper used to make banknotes in the United Kingdom to prevent forgery. To prevent large-scale economic damage from causing serious losses to the country, it has now been used to identify the authenticity of documents using security lines. very common. At present, about 80% of the world’s banknotes contain security threads. With the increase in the number of automatic verification machines, security line anti-counterfeiting methods have presented a brand-new situation and become more and more important and complicated. The basic form of the safety line on the first day was a 0.5 mm wide plastic tape, which was very obvious and easy to check. The earliest security line had the property of observing its presence under reflected light and an opaque band under transmitted light; later, the plastic safety line was metallized to further enhance its function in the banknotes. The area containing the metal wire is torn and it will feel its presence. However, banks generally do not allow this because it will speed up the damage rate of banknotes. The effectiveness of the security line to prevent the destruction of the country’s economy is very large, and a complex process is usually used to add some natural cellulose and man-made materials (plastic/metal) to the security line so that The general public is more aware of its existence. In the 1960s, some paper manufacturers, especially British Portals, added more complex safety equipment to the development of safety lines, such as the possibility of printing some micro-letters, codes, etc. Add color or UV fluorescent toner to the material. Gradually, the security thread is no longer merely a sign of authenticity, but it is also a carrier of some data, but its function was not strong at that time until the so-called "Standust" or "Windows" security emerged in the 1980s. Line, its true potential is fully excavated. Observing the Windows security thread under light is a "textured" line that appears on the front and back of the paper. This patent allows the security thread to have some additional security features, such as light diffraction, which will appear on the surface of the paper under different lighting conditions. Inventing a new thing and applying it in practice are two different processes. In practical applications, due to process constraints and requirements on the strength of banknote paper, it is difficult to realize the concept of "weaving" of windowed security threads on both the front and back sides of the paper. In practice, this new feature is only added on one side of the paper. While data carriers appear for the first time in windowed security lines, some engineers who develop security are also looking for reliable methods that can automatically confirm the authenticity of documents. The nature of the paper and the manufacturing process show that the paper fibers are not ideal carriers of machine-readable data and that the ink can only carry traces of detectable elements, and that these elements are also susceptible to wear and are susceptible to attack by chemical agents. The circulation cycle of banknotes is greatly shortened. The safety thread based on polymer is consistent and flexible, but it also contains a large number of features that the machine can detect. These characteristics exist in the form of magnetism (high or low magnetization), electrical conductivity, and charge luminescence. The main drawback of using a security thread as a carrier for data or signals is that it is generally parallel to the shortest side of the banknote, so that when reading with a high-speed reader, the relative time between the sensor and the features that can be detected is the shortest. . This is not a problem with low-speed identification or still-file inspection, but the problem is greater at high-speed reading. Over the past two decades, there have been many changes in the appearance of the security thread, from embedding the security thread to paper, to the application of demetallized text and pros and cons, and to the use of optical and hot chrome equipment. File security. Widespread use of security threads has led to a change in papermaking technology. Now some major papermakers use double-layer composite equipment to form paper. The next layer is a thicker carrier layer (possibly containing watermarks), and the upper layer has security threads. Either embedded or windowed, they form a composite layer on the carrier layer. This way the 3-4mm safety thread will not reduce the paper strength at all. Since the security thread is easy to see and read, complex features such as holograms, hot chrome text (text that can be activated by temperature), etc. can be added to them, which can greatly enhance the function of the security thread. What does the security line bring us? Whether it is now or in the future, security lines are undoubtedly the most common safety precautions added to paper. The security line also plays an important role in brand protection.