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https://doi.org/10.19279/TVZ.PD.2019-7-3-17

NEAR INFRARED SPECTROSCOPY OF COLORANTS IN SECURITY DESIGN OF POSTAGE STAMPS

Jana Žiljak Gršić orcid.org/0000-0002-1190-5003 ; Tehničko veleučilište u Zagrebu, Zagreb, Hrvatska

Sažetak

In honor of the 350th anniversary of the University of Zagreb, a commemorative postage stamp is issued to which our new security printing design method with NIR dual image called INFRAREDESIGN® is applied. This paper describes spectrography of light absorption in visible and near infrared spectral region for the colorants on this postage stamp. The description includes spectra of colorants as well as spectra of their separated components: cyan, magenta, yellow and key (black). Digital, experimental printing is a predecessor of a large circulation printing. There is a slight difference between colorant recipes (for the same color) prepared for digital printing and those for offset printing. IRD, applied in security of postage stamps, implies coloring that differently manifests itself in visible spectrum and in near infrared spectrum. Equal color twins with different colorant composition are introduced in “IRD numismatics“ technology. To meet the requirements of public tender for the postage stamp design, the design concept was executed by digital printing. In printing of securities there are two levels of execution, performed in two steps. Large circulation stamps are issued into the philatelist world by the method of offset printing. Both stages in the postage stamp production have the same colorants. Therefore, two groups of twins of security recipes for colorants are prepared in order to achieve the infrared security effect with respect to the requirements of both public tender documentation and large circulation for numismatics. Development of IRD technology allowed me to extend graphic preparation method in security printing of postage stamps under the name “VZ-PM separation“, which is a special type of Gray Component Replacement - GCR method.

Ključne riječi

Security graphics; NIR spectroscopy; computer graphics; IRD numismatics; INFRAREDESIGN®

Hrčak ID:

230597

URI

https://hrcak.srce.hr/230597

Datum izdavanja:

2.12.2019.

Posjeta: 456 *