This article presents results of a study of color separation for the near infrared wavelength area in case of a double image reproduction. One image is observed in the visible spectrum and another one is detected under near infrared (NIR) light. For the purpose of NIR separation (CMYKIR), discussion is extended to CMYK working space as a device dependent on comparing several printing technologies. CMYK process inks characteristics enable visualization of the same color tone in default color settings with the goal to create two independent images in the same print; two independent pieces of information recognizable under two different types of lighting. The new approach to image reproduction is based on the idea of controlling and processing several images incorporated into one reproduction. This article unites five principles which are set for processing near infrared image reproduction: the range of CMY into CMYK transformation, CMY invisibility in near infrared light, carbon black in NIR, gray and CMY gray, and device dependency of CMYK inks. The reproduction is observed selectively in wavelengths ranging from 400 to 1000 nm. Independent graphics may be graphics generated by algorithms, conventional images or texts. Information about its visible area is joined to each graphic. Detecting graphic work incorporated differently in a print with the help of the corresponding instruments is becoming a new chapter in security graphics, design, and informatics.
Klaudio Pap, Ivana Žiljak, Jana Žiljak Vujić, "Image Reproduction for Near Infrared Spectrum and the Infraredesign Theory" in Journal of Imaging Science and Technology, 2010, pp 10502-1 - 10502-9, https://doi.org/10.2352/J.ImagingSci.Technol.2010.54.1.010502