Ivana Žiljak

Infrared hidden CMYK graphics

Abstract The article presents a further development of new method of carrying out security graphics by programming color mixing for two separate wavelength areas. The first image is observed in daylight only, and the other image is observed separately under infrared (IR) light. Two independent graphics, two different pieces of information may be texts, vector or pixel images, and graphics generated by algorithms. Both images are printed simultaneously with CMYK printing inks only. In the near infrared range there are significant transitional phenomena that were not researched and targeted or applied. Many new measurements have been conducted describing the general relationship to set a new separation theory that has the goal of introducing the properties of infrared light in the reproduction of images. Targeted creating of two images is supported by the method of detecting their authenticity. The proof of the original print includes the characteristic of CMYK working spaces being device dependent. The application is in the security area on all graphic products, securities, documents, printed matter, packaging material, plastic products, works of art protection, product declarations, textiles and leather security, including brand protection.