## 3 Methodology  
Our applications of dual dyeing and expanded video surveillance are based on the properties of light absorbance of dyes for digital printing in the visible (V) and near-infrared spectrum (Z). Different color ranges--XYZ, HSB, and RGB--describe colors only in the visible spectrum of sunlight. In the printing industry, dyeing is done with dyes C, M, Y and K. The inkjet plotter used C, M, Y, K (HP Latex 330 Printer), as well as dyes for many other printing technologies, including offset printing. Dyes C, M and Y do not absorb NIR light. On the other hand, dye K (carbon black) strongly absorbs NIR light. The light absorption properties C, M, Y, and K are presented as spectrograms in Section 5. The CMYK is observed as a substance whose pigments absorb the NIR and the V spectra. We introduced a new chapter in programming (Prepress) for producing a dual image--an image with separate content for the visible and NIR spectrum--into the printing industry. \"Twin colors and dyes\" are defined as dyes of the same color in the visible spectrum that absorb light differently in the NIR spectrum. IRD is a fusion of two graphics that differ in the extended visual spectrum (RGB) and near infrared (NIR). The first image \"RGB\" is in the (print) colors C\({}_{0}\), M\({}_{0}\), and Y\({}_{0}\) (cyan, magenta and yellow). The second image \"Gr\" is set as a multicolored gray image for instrumental observation with a NIR camera. The second image is in 40% coverage with the dye carbon black K, which is responsive to surveillance NIR cameras. The IRD technology (replacing C, M, Y with K) has limitations. It is intended to replace the value of K by C, M, and Y exactly as much as the value of Z in the gray image Gr. The maximum replacement (GCR) of C, M, and Y by K from the Gr image was determined based on the minimum value of one of the components C, M, and Y. In hidden information design, the dual image for recognition with cameras already installed in the community is designed on clothes or work uniforms. The advantage of dual marking as \"expanded information\" is that it does not compromise personal integrity. The automatic recognition of vehicles and persons facilitates the effectiveness of law enforcement and traffic surveillance, and at the same time enables controlled monitoring of target groups, which significantly increases the safety of participants. Figures 1 and 2 present schoolbag covers that are designed for school children. The idea is that when leaving school or on field trips, children wear the class and school mark in the infrared spectrum while in the visual spectrum of the desired design and color without markings. Control and classification of persons is performed by hand-held, pocket detectors (IR money detector), which are commonplace and used in the verification of individuality. Figures 1 and 2 show the design of school bags with colorful flowers. Figure 3 shows a girl in a solid black colored jacket. In all three proposals, a hidden image with individualized text was added, which is colored with 40% coverage with black ink, K. The intention is to recognize the text only with an NIR camera. Marking for two spectral areas was the initial idea of this article, with the intention of raising the safety of participants in the urban environment. Cities and traffic centers are specific because of the large number of inhabitants with uniformly colored and tailored clothing. Monitoring traffic, squares, and shopping malls with the aim of raising general security has become a priority for all participants. The IRD method of marking clothing enables discretion, normal visual condition and quick recognition via surveillance Z-RGB cameras. We propose a more complex system of video surveillance in urban space with multi-purpose Z cameras. Cameras that have different, alternating, filters for detecting and recognizing information. Our first Z cameras had only one filter for 1000 nm. Today's Z cameras have up to a dozen filters, with the intention of bringing out expanded information [11].