The article gives an algorithm for near infrared region (NIR) that contains hidden information derived as a vignette in the security printing. The motif is implementation of line solutions for graphics that are designed with colors in the visual spectrum (VS) but with the double property: one picture response in the NIR and the other is seen in the VS (400-700 nm). The algorithm is based on Bezier method with symmetrical development and planned visibility using the specific properties of dyes, their absorption of light in the near infrared spectrum. The goal is to show type that is hidden from the human visual area and is presented in three conditions: completely invisible, transition state, and instrumentally visible under the 1000 nm. Relations and parameters are given for three different color tones, which are also procedures for the development of double images in the security printing. |
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