Considerable research over the last decade or more on the study of fluorescence has bore fruits in the form of development of new fluorescent dyes. These security dyes are now applied increasingly in the very sensitive area of security printing. The fluorescent dyes are providing ways to create and apply effectively controlled "signatures". The USP of these dyes are that they are customized and are printed as patches on different kinds of surfaces. Each of them has a signature element that is able to identify the patch as authentic. As the different dye formulas are able to vary their fluorescence characteristics in various repeatable ways, as a result unique signatures can be achieved. A very popular Example of a dye that is used in security printing is that of Coumarin 1. Which is represented by the chemical formula as given below.
Coming now to Luminescent pigments, these days a new range of luminescent has been developed that are either excited by UV or IR and applied in security printing applications. Here a few specific uses of the luminescent pigments in the security printing is discussed.
Security Printing and prevention of counterfeiting- Security marks and features that are not visible under normal light are made with Luminescent pigments. They cannot be duplicated even by the ultra sophisticated photocopiers. While they can be easily verified using a very simple Ultra violet light ora luminescence sensor. That is the reason for security printing of stamps, checks, credit cards, licenses etc. are done with Luminescent pigments.
Brand Protection and Security of Products- In applications that involves product security, Luminescent pigments are used in making tamper evident seals for pharmaceuticals and other products. When it comes to brand protection, luminescent pigments and fluorescent dyes are used for proprietary invisible security marks and features which gets printed on products, packaging and labels.
Property Identification and Prevention of loss- As the invisible security marks created by luminescent dyes are not visible under normal, do not deface the property and cannot be removed they are an ideal forensic tool.