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ISSN 2225-6067ISBN 978-3-9812704-5-7

1ar1ga1

dvances

ing andMedia

hnologyVol. XXXIX

N1ls Enlund & Mladen Lovrecek

Advances in Printing and Media TechnologyProceedings of the 39th International Research Conference of iarigai

Ljubljana, Slovenia, September 2012

Published by the International Association of Research Organizations for the Infommtion,

Media and Graphic Arts industries

Darmstadt, Germany 2012

Co-edited by Nils En lund , Helsinki , Finland

Mladen Lovrecek, Zagreb, Croatia

Scientific CommitteeAnne Blayo (Grenoble)

Timothys C. Claypole (Swansea) Edgar Dorsam (Dannstadt)

Wolfgang Faigle (Stuttgart) Patrick Gane (Espoo)

Ulrike Herzau-Gerhardt (Leipzig)Gorazd Golob (Ljubljana)

Jon Yngve Hardeberg (Gjevik) Gunter HUbner (Stuttgart)

Marie Kaplanova Pardubice) John Kettle (Espoo)

Helmut Kipphan (Schwetzingen)Marianne Klaman (Stockholm)

Yuri Kuznetsov (St. Petersburg) Magnus Lestelius (Karlstad)

Ulf Lindqvist (Espoo)Patrice Mangin (Trois Rivieres)

Erzsebet Novotny (Budapest) Anastasios Politis (Athens)

Anu Seisto (Espoo)Johan Stenberg (Stockholm)

Renke Wilken (Munich) Scott Williams (Rochester)

The facts published in thi s book are obtained from sources believed to be reliable. However, publishers can accept no legal liability for the contents of

papers, nor for a n y informati on contained therein, nor for conclusions drawn by any party from it.

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means of electronic,

mechanical , photocopying, recording or otherwi se without the prior written permission of the publisher.

ISSN 225-6067ISBN 978-3-9812704-5-7

Printed in Croatia by arodne Novine, Zagreb - October 2012

IV

Introducing a new anaglyph method: compromise anaglyph 91Jure Ahtik

Printing Braille with inkjet 97Manfred Schar, Urs van Arx, Fritz Bircher, Reinhold Krause, Pascal Bernet, Karl-Heinz Selbmann

Understanding graphic protection methods in print productionBranka Marie Kolaric, Ivan Budimir, Jana Ziljak Vujic

107

Accelerated light aging of digital printsAkos Borbely, Csaba Horvath, Roz(i/ia Szentgyorgyvolgyi

117

Reproduction of art paintings with their status in the near infrared spectrumJana Ziljak Vujic, Ivana Ziljak Stanimirovic, Ana Hoic

123

2. Deterrninators of quality in printed products

Towards a fully digital computer-to-screen workflow for an improved product quality and quality assurance in screen printingJanko Jesenko, Bojan Petek

131

Leaner and better. How can the setup time and waste at the sheet-fed presses be reduced?Csaba Horvath

Digitisation of old printed typefaceKlementina Moiina, Tanja Urbane

139

145

Surface patterning of flexo plates for improved ink transferAnja Hamblyn, Davide Deganello, Tim C. Claypole

153

Effects of solvents on flexographic printing platesAlexandra Theopold, Jann Neumann, Daniel Massfelder, Edgar Dorsam

159

Permanent flexographic plate changes through nip contactsDavid Beynon, Tim C. Claypole

169

Ink splitting: The influence of structured surfaces on the contact angle in tlexo printingStefan Griesheimer, Edgar Dorsam

175

The influence of engagement on the tlexographic printing of fine linesTim C. Claypole, Gyln R. Davies, Simon M Hamblyn, David Galton, Richard Hall

181

Effect of tlexographic press parameters on the reproduction of colour imagesTim C. Claypole, Eifion H. Jewell, David C. Bould

187

Developing a laboratory simulation of tail edge pickEveliina Jutila, Cathy J. Ridgeway, Patrick A. C. Cane

195

Control of the breakup of ink filaments in offset printingJames Claypole, Phylip R. Williams, Davide Deganello

207

Hardness and electric conductivity of copper in gravure form productionArmin Weichmann, Mallhias Galus, Tim Wolber

213

Characterization of gravure cells using confocal microscopyNils Bornemann, Tim Guck, Thorsten Bitsch, Edgar Dorsam

221

ZI LJ AK-V U JI C ET AL.: R E PROD UCTION O F AR T PAINTI NGS W ITH TH E IR STAT US IN TH E EA R IN FR A RE D S P ECT R U M 123

Reproduction of art paintings with their statusin the near infrared spectrum

Jana Ziljak-Vujic 1, Ivana Ziljak Stanimirovic 2

, Ana Hoic 3

The Polytechnic of ZagrebVrbik 8, HR-1 0000 Zagreb, Croatia

E-mail: janazv@tvz.hr

:Faculty of Graphic Art ZagrebGetaldiceva 2, HR-1 0000 Zagreb, CroatiaE-mail : ivana.ziljak@grf.hr

3 Museum Mimara, ZagrebRooseveltov trg 5, HR-10000 Zagreb, Croatia

Abstract

Each work of art has its own specific response in the infrared spectrum. An artist's paints have different response characteristics in the infrared spectrum. Process inks in printing reproduction also have different properties in the infrared spectrum. The initial assertion in this paper is that the infrared status of a work of art can be reproduced with RGB I CMYKIR separation. The target is to have the reproduction and the original work be equated to the utmost extent in the visual and infrared spectrum. This initiates discussion on the necessity to extend "conven tional color management" to the range of 400 to I 000 nanometers.

The RGB experience of reproduction extends the zero separation rules with the addition of Z separation. Each RGB picture pixel is calculated in the CMYK conversion respecting the independent pixel value in the Z picture. CMYK become mutually dependent values but with the goal for carbon K to be closest to the Z status of the work of art's infrared value. Channel K acquires a new meaning. It is a separate picture, the picture observed by the infrared camera. In future artists will deliberately paint double pictures, one for the visual and the other for the infrared area. Printers and graphic designers will face a new task: to interpret a work of art in such a way that the reproduction has separate states in the visual and infrared spectrum.

Keywords: infrared technology, art reproduction, CMYKJR separation, Z value of infrared, safety in painting, hidden painting.

1. Introduction

Let us name it as the Z status. We distinguish the RGB image, the conventionally scanned status for the v isual spectrum. The reproduction by printing procedures is into the CMY space, but without using UCR, GCR or UCA methods. Channel K is empty, i.e. the separation is in "non" conditions.

We scan the infrared status of the painting with a ZRGB (Ziljak et al., 2011) camera. Separation with an external picture is proposed according to the CMYKIR (Ziljak et al., 2010) theory that will determine the co verage in channel K. The goal is reducing coverage in channels C,M,Y with the Z data as the value of the future K channel.

The requirement is set for channels C, M, andY that the reproduction should be of the same quality as that of conventional graphic separation. Channel K is carried out with carbon black colorant because it has a res ponse in the infrared spectrum (Pap et al.,201 0). A reproduction is obtained that has light absorption in the form of the Z picture, observed after applying the ZRGB scanner.

Artists have not been aware of their works of art having different states in some other spectrum such as: the ultraviolet, X-rays, gama or infrared spectrum. The most highly estimated works of art are studied today in the said sunlight wavelengths. Artists did not have instruments to measure this. They were very far from the idea to take advantage of colorants in other wavelengths and to paint a double picture on purpose. The future of painting art will change, as well as the future of reproduction photography. Such artistic and printing acti vity was demonstrated for the first time at IARlGAI in Budapest in 2011 : a reproduction that contains two different states of a work of art; one that is observed by the human eye and the other by an instrument in the infrared spectrum.

124

Figure 1 a, b: The painting's visual status (a) and inji·ared status (b-ZO)

2. CMYKIR separation and reproduction of artistic works

The near infrared status of the original was planned by the artist Nada Ziljak. She forced out the invisible picture, Figure 1 b, hidden in picture, Figure I a. Reproduction with merging of the two pictures was carried out with the ZRGB program. Reproduction with the CMYKIR (Ziljak et al., 2009) method resulted with the picture that has CMYKIR channels - Figure 2.

Figure 2: Channels C, M, Y, and K, after CMYKJR separation

)

I!+ 1187

• '-VUJIC ET AL.: REPRODUCTION OF ART PAINTINGS WITH THEIR STATUS IN THE NEAR INFRARED SPECTRUM 125

.' lR channel differs from the Z0 state of the lR picture. This is explained by the fact that painting colors are different in respect to the CMYK colorants for conventional graphic reproduction. A painter's colors

"lOt cyan , magenta or yellow. Artists use dozens of different colors, they mix them further to obtain more_ and they do not u se screening technology. These colors are reproduced by the printing industry using

:. Y printing inks, with the help of additive and subtractive technology. C, M, and Y process inks gene- do not have positive absorbing properties in the near infrared spectrum. Their Z value (Ziljak et al.,

_ _ is zero. Carbon black is also used in InfraredArt interpretation. It is a colorant that acquires a new mea= :n graphic reproduction. It becomes the carrier of the infrared component of the a rtist's original work of

KIR (Ziljak et al. 2009) separation is a pplied. With the help of this technology an endless number e is simulated on the painting's canvas.

e are painting colors of light shades that have absorption in Z space, and those colors that do not have baracteristic of absorbing infrared light.

Table I : Painting colors in the visible and inji·ared spec /rum

WINSOR & NEWTON, Harrow, Middlesex, GALERIA COLORS

ACRYLIC Lab RGB VS (0 - 28Gray(%) VS Z(%) 1000 nm IR

Ultramarin 35, 46, -93

Prussian 1, 0, 0

,_ 1 47, 59, 231 85

1199Blue Hue 9,10,12

Cobalt Blue 27,39,-80 11 32,48,187Deep Turqueise 22,-9,-25 Iao.61,90 90

+ 2,98,63 1178Olive Green 38, 23, 18+

Silver 83, -1,4

1, 55, 38 - 34

REEVES 207, 207'199 32Burnt Sienna 39,46, 38Opaque

Burgundy 27, 36,13 ,40, 50 9

artist mixed the colors in such a way that she obtained the same shades with the following cteristics: firstly, they also have a strong response in the first half of the near infrared spectrum Z (800

:1 00 nanometers), as well as in the visual spectrum (V; 400 to 700 nm), and secondly: they have a strong-S?Onse only in the V and not in the Z area.

Figure 3. a, b: Portrait and a cal, acrilic on pa per, Inks and control ofZfi'om Table I

:be artist has created a work of art that has two different stories. She has hidden part of her mtunate_ otions from the public eye. Her collection posed a question to graphic and fisca l experts: can a repro

tion be made that contains two pictures in the same way as the original does? Any attempt at forgery omes infinitely difficult, almost impossible. Such an expert should paint the picture observed in the V ce, but also the other picture that is seen in Z space. Therefore, only dual painting becomes "security pain g", secured by the painting's author.

126 ADVANCES TN PRTNTTNG AND MEDI A TECHNOLOGY, VOL. XXX I X (201 2), 1 23-1 27

Figure 4: Visual and Z (N!R) state of art colors

The final reproduction (by merging C,M,Y and K channels) is good quality interpretation of the initial pic ture. The CMYKIR separation requires precise knowledge of the colorsetting for determining which colo rants will be used for printing the reproduction. In Figure 2 the channels are separated for SWOP colorset ting. This means that the reproduction will hide the Z picture completely only if SWOP colors are used. If other colorants are used, the hidden Z picture will show through . CMYKIR separation must be repeated for them with parameters and the mathematical model for printing conditions determined by the other color setting. The algorithms for the digital Xeikon printing have been published (Pap et a!., 20 I 0), as well as se veral other analytical CMYKIR separation procedures.

Checking separation results can be carried out by the con ventional procedure of joining CMYK channels in Photoshop. For channels in Figure 2 it is necessary to load the SWOP colorsetting. If this picture is trans posed into the RGB status, then once again into the CMYK status, - the graphic display of the Z status disappears.

The second experiment in respect to the CMYKIR status sensitivity is checked by only changing the color setting in the Photoshop program. The Z separation status begins to show through. It becomes visible. Also, a wrong choice of process dyes, an inadequate printing technology and unplanned choice of substrate material for color printing become evident.

The graphic production dual status has a deeper background in respect to the graphic product security. Prin tings, especially those on wrapping material, acquire new value. They are also checked in a new manner as to authenticity. Z cameras have been developed for this purpose and they can recognize the infrared component of the solar spectra. Checking is carried out in daytime or under artificial light that has at least a small part of the Z component. Of course, all this is also possible with control security cameras in the nighttime recording mode: with cameras that have their own source of IR light.

3. Conclusion

We are setting a new method for reproducing paintings that contains the original painting's status both in the V and the Z spectrum. The book, monograph, the exhibition catalogue acquire new value. The original paint ing's status in the near infrared spectrum has been introduced into the reproduction, together with the status in the visual wave length of color recognition. With each copying of the graphic print with VZ statuses, the Z status disappears. Thus a new method for securing graphic reproduction has been set.

The painter Nada Ziljak creates a picture with the target being a double status of her work of art; two depen dent pictures that are at the same time independent. They are linked and separated by their contents. Because of this double meaning, printing reproduction is also faced with the task to have two versions, two stories. The reproduction will be observed in two ways, in the same way as the original: with the eye and with the camera.

Reproduction inks may be spot inks, such as Panton inks, for example. For them it is necessary to measure Z values of light absorption at 1000 nm (Ziljak et a!., 2012). The artist also carries out this procedure of mea suring Z values for her artistic colors. This is a new target in printing color reproduction.

J. ZILJAK-VUJIC ET AL.: REPRODUCTION OF ART P AINTINGS WITH THEIR STATUS I THE NEAR INFRARED SPECTRUM 127

References

Pap, K., Ziljak, 1., Ziljak-Vujic, J., Image Reproduction for near infrared spectrum and the infraredsign theory. IIThe Journal of Imaging Science and Technology. 54 (201 0) , I ; I 0502 -I-10502 -9

Ziljak, V., Pap, K., Ziljak, l, CMYKIR security graphics separation in the infrared area. II Infrared Physics andTechnology. 52 (2009), 2-3; 62-69

Ziljak , V., Pap, K., Ziljak, 1., Infrared hidden CMYK graphics. II Imaging Science Journal. 58 (20 I 0), I; 20-27

Ziljak, V., Pap, K., Ziljak-Stanimirovic, I., Development of a prototype for ZRGB infraredsign device IITechnical Gazette. 18 (20 II) , 2; 153-159

Ziljak, V., Pap, K., Ziljak-Stanimirovic, 1., Ziljak-Vujic, J., Managing dual color properties with the z-parameter in the visual and NIR spectrum. II Infrared Physics & Technology. 55 (2012) ; 326-336

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