This study focuses on the properties of reflection and absorption of light in the visible and near infrared range of acrylic dyes and related materials for coloring. The research aims to understand the use of acrylic dyes in fine arts and to simulate these dyes for printing purposes. Two groups of acrylic dyes were studied using spectroscopy to determine their light absorption properties in the visible (VIS) and near infrared (NIR) regions. The measurements were performed with forensic cameras equipped with 24 light filters in the range of 400–1000 nm. The results of the digital recordings were compared with video surveillance cameras that operate and record during the day and night. The same color had at least two formulations of dyes for print reproduction to simulate what the naked eye sees and to simulate light absorption in the NIR spectrum. The study aimed to gain a deeper understanding of the properties of acrylic paints and related materials, considering how they can be used in fine arts and how to simulate them in printing.

In this paper, the fusion of four graphics into one integrated graphic is selectively observed in the visible and infrared spectrum. Each graphic represents its own information derived from the following sources: vector graphics, drawing, photograph and textual information. One graphic will be visible to the naked eye after the print. The other graphics will be observed with an NIR surveillance camera. These other graphics are nested into the selected visible graphics. All the graphics together make up a security print product with the characteristics of an individual solution with multilayered elements. Reprinting is possible only for the person in possession of the solution created according to the algorithm based on the INFRAREDESIGN^® method. When these graphics are printed on paper, it is impossible to produce an identical graphic prepress (C, M, Y, K) to produce forgery with the same dual properties in the visible and NIR spectrum.

Transparent linear NIR digital graphics with the intention of security information were printed on a polypropylene material. A label for expensive juices in transparent glass or plastic packaging is demonstrated. Obligatory information about the contents of the liquid was made to be read with the naked eye. The “Z” (near-infrared) information is expanded with data integrated for joint digital printing. This data does not disrupt the original, planned visual appearance of the label, “V” (visible). Although the two graphics are in the same place, the IR graphics on the label cannot be discerned with the naked eye. This brings elements of secrecy and protection against attempts to counterfeit the contents of the transparent packaging. The separation and recognition of the two pieces of information, V and Z, are achieved with a security camera in the near-infrared mode or with one of the many NIR detectors that surround us. In the article, the “VZ” algorithm for the integration of two independent graphics and the limitations set by digital printing are published. Toner properties and the method for developing the recipes for the composition of twin colorants for two spectral ranges are presented using spectroscopy.

Smart polyester materials with embedded near-infrared (NIR) functionalities offer a promising pathway for low-cost, covert tagging, and object identification. In this study we present the development and characterization of polyester packaging surfaces printed with spectrally matched twin dyes that are invisible under visible light but selectively absorbed in the NIR region. The dye patterns were applied using a Direct-to-Film transfer (DTF) method onto polyester substrates. To validate their optical behavior, we applied a dual measurement approach. Laboratory grade NIR absorbance spectroscopy was used to characterize the spectral profiles of the twin dyes in the 400–900 nm range. A custom photodiode-based detection system was constructed to evaluate the feasibility of low-cost, embedded NIR absorbance sensing. Results from both methods show correlation in absorbance contrast between the dye pairs, confirming their suitability for spectral tagging. The developed materials were evaluated in a real-world detection scenario using commercially available NIR cameras. Under dark field conditions with edge illuminated planar lighting, the twin dye patterns were successfully recognized through custom software, enabling non-contact identification and spatial localization of the NIR codes. This work presents a low-cost, scalable approach for smart packaging applications based on optical detection of actively illuminated twin dyes using accessible NIR imaging systems.