INFRARED SECURITY PRINT Ivana Žiljak, Klaudio Pap, Jana Ž. Vujić
Faculty of Graphic Arts, University of Zagreb, CROATIA



Conventional graphic theory of color printing, practice and color managementhas in focus a high quality reproduction visible in the spectrum to our eyes - daylight.
Separation: RGB – CMYK with GCR, UCR, UCA control developed only for daylight 400 – 700 nm

New separation method

Observing images with instruments covers areas with shorter and longer wavelengths in respect to the visible part of spectrum.
We are determining the method of combining printing inks with managing the infrared response in the range of 700 to 1000 nm wavelenghts.

RGB – CMYK           = CMYKIR

Our CMYKIR separation method means addition of a new variable in combining process printing inks that will carry information on provoking reaction to Infrared radiation.

Daylight                                         Infrared

Software for Infrared

We developed software solution for applying  all printing techniques with control in the infrared output           

The CMYKIR ideais based on facts:
eigenvalues of CMYK printing inks

  • The same tone color can be achieved at the infinite variety of ways
  • CMY and K respond differently in Infrared light
  • It is possible to replace CMY printing inks with carbon K printing ink for the same hue / tone of color
  • This freedom allows programming targeted CMYKIR separations


Double separation  CMY / CMYKIR

Two opposite black colors:

  • Black which is generated by mixing CMY components which is not visible in IR wavelengths.
  • Black color “K” called «carbon black» which is visible under Infrared radiation.

Two opposite black colors visible in daylight...but

Daylight                                                  Infrared

BLACK: CMY = not visible in Infrared light
BLACK: K = visible in Infrared light

Other colors CMY

Depending on the nature of pigment:

Cyan is visible up to 750 nm.     
Magenta is invisible above 600 nm.
Yellow is invisible above 650 nm.

Daylight - Input two picture: 1. Split & 2. Dubrovnik
In daylight 380-600 nmwe see only town Split
Double separation CMYKIR

Infrared - 800-1000 nm
The picture of Dubrovnik is incorporated in picture of town Split.
In 1000 nm only Dubrovnik is seen.

Daylight                                                         Infrared

Daylight                                                         Infrared



stochastic algorithm: hidden portrait is visible in the IR light


Books 2007 – 2009.
ESIGN” & “Infrared security graphics”

Patent number

The new Book “Infrared security graphics”

  • 100 examples, printed with Infrared effect
  • The book can not be copied with the same appearance of the planned IR Graphics
  • IR solutions for vector, pixel graphic, stochastic algorithms, colored barcodes, Infrared on textile
  • Examples are presented with IR camera

Daylight                                                Infrared





Daylight                                                Infrared

Daylight                                             Infrared

solution with two individual screen element            In IR we can see only one screen element

Applying on post stamps

Colored barcode !


  • CMYKIR separation is done with conventional process colours
  • for its application, the new knowledge about the graphic profession is necessary
  • basic motivations for applying INFRAREDESIGN are design, individualization and security
  • The planning of visibility and invisibility of IR area enables the protection of all graphic color products and the protection of printing-houses


Usage possibilites brand protection

All graphic products:
Securityes - douments, banknotes
Diplomas, certificates, contracts,...

Newspapers, magazines, books,...

Packaging: infrared graphics + infrared barcode
Product declarations and finacial stamps

Protection and assessment of original art / oil, acril

Textil and leather products

Daylight                                                Infrared

Daylight                                                Infrared