In an effort to get ahead, and to stay ahead, of increasingly sophisticated counterfeiters, the US government is looking to a refractive lens technology that will provide additional security for the $100 bill. Each C-note will display an image — exactly what image remains under wraps — that slides around the surface of the bill in a way that is sure to grab attention. “It’s rather eye-catching. You start playing with this material like it’s a video game,” said Douglas Crane, vice president of Crane & Co., a Dalton, Mass., company that manufactures all of the paper used for US currency. The company has a contract, estimated by the government to be worth $46 million, to produce the new security threads that will be incorporated into the paper before it is shipped to Washington for printing.A thread laden with microlenses will be used as an anticounterfeiting measure in future $100 bills. This is a section of material that is fed into the paper machine during sheet forming. The machine produces a roll of paper with the thread material windowed into it. This roll is converted into sheets, printed and further converted into currency. Courtesy of Crane & Co.Although the newly modeled bill may amuse consumers, it likely will stymie counterfeiters who will be faced with a technology that is difficult to understand, never mind replicate, according to Crane. Specific details of the technology are not being released, but Crane said that it involves refractive technology that is based on a thread laden with microlenses. Each bill will have an optical thread containing hundreds of thousands of lenses, which then is woven or windowed into the paper such that the thread is exposed in certain areas of the surface of the bill. The thread will be several millimeters wide, though far thinner than a 100-μm-thick bill. When incoming light strikes the optical thread, the lens system produces a pattern or image that seems to slide over the thread’s surface as the viewer changes the bill’s angle.The technology was developed in recent years by a US company that has a partnership with Crane, and it has since been incorporated into the Swedish 1000-krona note. The Mexican government intends to use the security thread in some of its currency, and other countries also are looking at the technology for their notes.Various anticounterfeiting measures already are built into US currency, but it is a never-ending struggle to keep ahead of those who would rather print money than earn it. Counterfeiters range from domestic novices with laser printers to suspected foreign governments who have the latest printing technology and the will to undermine US currency.Crane said that the technology has the potential to become one of the biggest anticounterfeiting measures in recent history. “There’s nothing else out there that behaves like this.”He said that as many as one billion $100 bills are printed every year and that it is the denomination most targeted by counterfeiters. The new $100 bill could be ready for circulation within two years, although no release date has been set. According to Crane, if the enhanced $100 bill is successful, other denominations could follow.