US Patent 7963450 Near infrared ink security feature

Systems and methods of providing a covert security marking for items such as documents, packaging, credit cards, and other valuable goods to combat the steady increase in forgery, counterfeiting, and other fraudulent activities is presented. A spectrally narrow, near infrared ink system serves as the basis of a covert security feature for items of value. Alternatively, or in combination, metal oxides having a substantially narrow absorption band and a maximum absorption wavelength of electromagnetic radiation in the near infrared range are also utilized.