The 'LuminusR' that you see in the title of this paper is a registered trade mark of a security paper product which has patent protection to date in six countries, including the United States. Further patent applications are in progress in over forty other countries. The essential characteristic of LuminusR Paper is that it contains a coloured image that is substantially undetectable when viewed in reflected light but becomes apparent when viewed through transmitted light. The stronger the light source, the more pronounced the image becomes. The purpose of this paper is to explain the technical aspects of the product and to explain, in effect, why it is a patentable, completely new technology for protection against counterfeiting. First, it must be explained that the inventors set out to develop a paper that, in conjunction with the surface print on a document, could not be reproduced by the normal means open to a counterfeiter: especially colour photocopying and Offset printing. During the time that Domtar proceeded to bring the concept to the stage of a commercial product, three other advantages became apparent: (1) Durability in use as proven by lab results and a 'live' circulation trial. (2) Design flexibility: giving a third 'side' to the paper that can receive a design. (3) Processing ability in existing equipment including printing presses and cash handling machinery. I am going to concentrate, however, on the anti-counterfeiting aspects of LuminusR Security Paper as security is the theme of this conference. In this respect, I will cover the following subject areas: (1) Make-up of the product, including production methods; (2) Security elements that can be incorporated to deter counterfeiting; (3) Health and safety aspects; (4) Testing against counterfeiting and simulation; (5) Cost-benefit of the product. I am also going to concentrate on one end-use, bank notes, although LuminusR paper has been tested through use in other security documents, in particular travel documents such as passports and visas.