Spot Colorant Twins for Infrared security print of Topographic Maps

Ivana Žiljak Stanimirović¹, Maja Matas¹, Matej Pogarčić², Jana Žiljak Vujić³

¹University of Zagreb Faculty of Graphic Arts, Croatia
²University of Ljubljana Faculty of Civil and Geodetic Engineering, Slovenia,
³Polytechnic of Zagreb, Croatia,

Abstract

Documents, securities and security printing products are designed with line graphics and the individualized raster. Topographic maps are a part of the protected graphic products group. We define them with several colors, up to seven colors. We perform the splitting of each color into the color twins, with the same color tone but within a different system. Group V dyes absorb only the visual light range from 400 to 700 nanometers. Group Z dyes absorb the infrared and the visual light. The infrared camera "sees" and recognizes only the infrared component at point Z of 1000 nm. In this way we plan the selection of isolated information on the protected document. The security graphic consists of 14 spot dyes and 14 layers; they are printed in offset. For the digital print, we simulate 14 dyes with the four color print. We have developed an algorithm wich combines these 14 dyes in the CMYKIR system. The elements of infrared security print for the geographic information
system are introduced as a new solution to protect digitally recorded information. The importance of topographic map digital data and digital press lays in the protection of the data accuracy. Modern scanning technologies and the digital press create forgeries which make it hard to identify the original document with correct information. All the present information is stored in the digital form. The easy editing possibilities with the advanced technology of digital media, digital printing and scanning make questionable the correctness of the information provided. Elements of infrared security printing for the geographic infomation system is introduced as a new solution for protecting digitally recorded data. By applying protective infrared characteristics to the digital record, the possibility of rapid verification of the documents is made possible. Access to accurate data and authentication is provided with the design of security elements hidden within the digital information. The mathematical model for the extraction of the infrared condition with digital print, according to the Infrared theory, is the basis for the formulation of the dyes mixing for the seven color infrared protected press. The new models are tested via digital printing where the spot twin colors are simulated: green, yellow ocher, light blue, dark blue, dark red, brown and black.

Keywords: topographic maps, spot twin colorants, Infrared digital print, CMYKIR separation, security graphics

1. Introduction

 Topographic maps contain important geographic data. The data accuracy must be authentic. In the past there was no security for this state document. Changing information was easily achieved through scanning and further digital manipulation. The original digital file needed to have a security feature which made it easy to detect an unauthorized change in all of the reproductions. Authors of  the maps needed to protect their work. Their authentication is also a quality and accuracy guarentee for the map user.
We sett new models of twin colorants [1] with the goal to incorporate the INFRAREDESIGN® [2] security for print of topographic maps. All maps have the double image V and Z [3] which is viewed with the ZRGB camera [4]. The colorants in the twin system were promoted on the IC Conference in Toronto [5]. The theory of the CMYKIR separation is  mentioned for the first time in 2009 [6]. The IRD theory is sett in 2010 [7] after which over 20 scientific works have been published on the subject of the IRD technology.

2. Layers

Topographic maps are created in layers. Each layer is joined by a special spot color. Color height, by beige tones. Forests and meadows are marked with several shades of green. Blue marks the water. Different aspects: river, sea, the sea depth, rames of rivers and bay names on the sea. Each concept joins its shade of blue. The correction, editing and changing of information on the topographic maps is done in layers. Printing is done with spot colorants for each layer separately. Such graphic work is done, usually, in the offset technique. If the press is interpreted with many colors, then the prepress depends on the product circulation. Small circulation seeks an optimization of the printing technology. Some layers merge. For example, blue is combined into a single printing form. Different shades are screened. This allows more or less light simulation of planned colors, but only one at a press fit. A very small print runs are performed digitally printed. All layers are then interpreted by a four-color process printing.

Fig. 1 a) black layer with general information; b) brown layer with hights

There is many different type of data on the black layer. They are: names of the places, buildings, roads, topographic meassuring positions, names of the regions. This layer is ideal for the seperation of black colorants with the different Z values [8]. In Tab. 2. the recipe for 2 Z states is given: zero and Z40.  The experiment of the CMYKIR separation in this work was processed by the black layer (Fig. 5). The buildings and area names were divided from the rest of the information on the first black layer.
  

Fig. 2 green layers; a) fields and forest b) borders of green areas

Fig. 3 blue layers; a) light blue for the water area, b) dark blue for the river borders and sea depth.

The National Geodetic office set rules for the analog and raster digital map production. The specifications control the quality of the production. It describes the technical characteristics such as content, color, shape, symbol. The depth of the rasterized map color is determined by applying a special 8-bit color table. Number and color names are defined with the color key (15 colors), with two additional colors (background and white) - The total number of colors in a digital file is 16 (Table 1). The way of translating the colors to digital four color print for one-time, experimental or developmental view of the topograhic map is not determinated. Such digital printing is done (in practice) on large B0 plotters. There is a question of granting the prepress for the massive offset.

Tab 1. Colors specifications for the digital raster data set by the National Geodetic office

 3. Security print

The paper defines the use of infrared technology for the design of dual information on multicolor spot print for topographic maps security print. The importance of introducing a security dimension in the area of ​​digital maps is defined in this work. Our work brings news of an expanded printing IRD principle. Security printing is required by the owners of printing houses, the authors of text and images, booksellers. 

Very small print runs are digitally printed. All layers are then interpreted by a four-color process printing.  Graphic products printed with four process colors can be easily scanned. Owners of topographic maps and printing houses have a great business loss. We propose the introduction of infrared technology in digital printing. Each layer is separated into at least two levels: the visual and infrared part of the Z section [8]. We got twice as many layers. But digital printing will separate layers with infrared characteristics. Everything is done and printed with the conventional method. The new imprint has infrared characteristics. Such topographic maps can not be photocopied.

Table 2. Twin colorants for topographic maps

In this paper, we consider seven colors. The proposal is that each color is separated into twins. IRD graphics can not be scanned while maintaining the characteristics of Z values [8]​​. Joining the individual parts of the individual layers V and Z dyes allows cartographers and specialists to determine the purpose of topographic maps. For the purposes of this paper, the color black is separated into two black dyes.

Fig. 4 Spot colors in CMYKIR separation

All layers are black / white. They carry color (information about RGB, and Z) for the transition from the visual condition in the joint separating the V and Z values.

Fig. 5 visual map and infrared black channel ; video animation - visual / infrared:
http://www.infraredesign.net/video/IR101Senj.html

The two state-Z separation is demonstrated on the topographic map of Senj. The reproduction has two images: the map as a whole and only the buildings. The buildings and area names are the only visible objects in infrared on 1000 nm. They are identified with IR glasses. In this example geographic information is shown. The hidden and the visible image are from the same geographic area. 

4. Conclusion

Topographic maps as a national document are important in determinating ownership, location etc. They are not protected and need a system for securing their content .With IRD, we have introduced a new type of protection for topographic maps. We developed a new security feature for the digital data using spot colorant twins. Colorant twins integrate two spectrums ranging from 400 to 1000 nm. Twins of different color tones are determined by the values ​​of the coverage with the process colorants C, M, Y, K. Data accuracy of geographic information is provided with spot color twins. While visually remaining the same, the spot colorants have an reaction in the infrared system. The topographic map is given a double condition of infrared extended reality.
All the procedures that allow detail modification on the topographic maps remain the same as before the IRD sublimation. Changes are performed separately on each layer. 14 spot dyes are implemented in 14 layers.
Connecting Layers for the IRD process has a significant benefit. The production will become cheaper. Infraredesign technology is applied also for offset printing.
This work brings an new approach to protecting digital geographic information. Rapid document authentication is made possible.

5. Reference

[1] Jana Ž. Vujić, Ana Agić, Nikolina Stanić Loknar, Picture information in expanded color management from visual to near infrared spectral domain // Technics Technologies Education Management, Vol. 8, No3 / 2013 p:1466 – 1477

[2] V. Žiljak, K. Pap, I. Žiljak, "CMYKIR SECURITY GRAPHICS SEPARATION IN THE INFRARED AREA", Infrared Physics and Technology Vol.52. No.2-3, ISSN 1350-4495, Elsevier B.V. DOI:10.1016/j.infrared.2009.01.001, p: 62-69, (2009)

[3] Martina Friščić, Olivera Međugorac, Lidija Tepeš, Denis Jurečić, Invisible information on the transparent polymer food packaging with Infra V/Z technology, TTEM Vol 8/4,/ 2013; P: 1512 -1519, ISSN:1840-1503, e-ISSN 1986-809X

[4] Žiljak, Vilko; Pap, Klaudio; Žiljak-Stanimirović, Ivana. DEVELOPMENT OF A PROTOTYPE FOR ZRGB INFRAREDESIGN DEVICE. // Technical Gazette. 18 (2011) , 2; 153-159

[5] Ivana Žiljak Stanimirović, Jana Žiljak Vujić, Maja Matas, INFRARED COLORANTS AS TWINS FOR SECURITY PRINTING OF DOCUMENTS AND SECURITIES, 45th Conference of the International Circle of Educational Institutes for Graphic Arts Technology and Management (IC), Toronto, Canada 2013

[6] V. Žiljak, K. Pap, I. Žiljak, "CMYKIR SECURITY GRAPHICS SEPARATION IN THE INFRARED AREA", Infrared Physics and Technology Vol.52. No.2-3, ISSN 1350-4495, Elsevier B.V. DOI:10.1016/j.infrared.2009.01.001, p: 62-69, (2009)

[7] Pap, Klaudio; Žiljak, Ivana; Žiljak-Vujic, Jana; Image Reproduction for Near Infrared Spectrum and the Infraredesign Theory, Journal of Imaging Science and Technology, vol. 54, no. 1, pp. 10502-1-10502-9(9) (CC, SCI, SCI-Expanded) 2010

[8] Žiljak, Vilko; Pap, Klaudio; Žiljak-Stanimirović, Ivana; Žiljak-Vujić, Jana. Managing dual color properties with the Z-parameter in the visual and NIR spectrum. // Infrared physics & technology. 55 (2012) ; 326-336.