UNiVTRSITY CIF hIOVI SAD

FACULTY CF TECHNiCAI SCi=I'{C[S

DEPARTI,.4FNT CF GRAPHIC ENGIhJITRING AND DTSIGh:

7'^ TNTERNATT'NAL sYMPosruM oNT GRAPHIc ENGINEERING AND DESIGN PROCEEDINGS

Novembcr 13-,14, ?014

I'i*vi 5ad, Serhia

Proceedings - The Seventh lnternational Symposium GRID 2014

PUBLISHER:

FACULry OF TECHNICAL SCIENCES

DEPARTMENT OF GRAPHIC ENGINEERING AND DESIGN

21 000 Novi Sad, Trg Dositeja Obradovica 6

EDITORIAL COMMITTEE:

PhD DragoLjub NovakovicPhD Igor Kartovic

PhD Sandra Dedijer

TECHNICAL SECRETARY:

MSc Ivana Jurid

EDITOR:

PhD DragoLjub Novakovic

LAYOUT AND PRODUCTION:

GRID team

PRINT:

Grafidki centar GRID, Trg Dositeja Obradovica 6, Novi Sad

CIRCUIATION:

300 copies

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INTERNATIONAL Symposium on Graphic Engineering and Design

GRID Q;2014;NoviSad)

Proceedings / Tthlnternational Symposium on Graphic Engineering and Design

GRID 2014, November 13-14,2014,Novi Sad;

[organizer] Faculty of Technical sciences, Department of cra_n!1c Engineering and Design,

Noii Sua;tco-organizers Faculty of GraphicArts,Zagreb and ObudaUniversity,Institute of

Media Technology, Budapest, Hungary; editor Dragoljub Novakovi6]. -

Novi sad: Faculty of Technical Sciences, Department of Graphic Engineering and Design,

2014 (Novi Sad: Grid). - 476 stt.: ilustr'; 30 cm

TiraZ 300. - Bibliografija uz svaki rad-

ISBN 97 8-8 6-7 892-645 -7

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SCIENTIFIC COMMITTEE

President Prof.PhD Dragotjub Novakovic, Focutty of Technicol Sciences,Novi Sod [SRB]Prof.PhD Wotfgang Faigte, HDM, Stuttgort [GER]Prof.PhD Thomas Hoffman-Watbeck, HDM, Stuttgort [GER]Prof.PhD MaLferd Verfet, IFRA, Dormstodt [GER]Prof.PhD Lidija Mandic, Foculty of Grophic Arts, Zagreb ICRO]Prof.PhD Mirostav Gojo, Foculty of Grophic Arts, Zogreb ICROJProf.PhD Diana MiLdic, Foculty of Grophic Arts, Zogreb ICROJProf.PhD Diana Gregor - Svetec, Focutty of Noturol Sciences ond Engineering,Ljubljono (SLO]

Prof.PhD Al.e5 Htadnik, Focutty of Noturol Sciences ond Engineering,Ljubtjana [SLO]Prof.PhD Tadeja Muck, Foculty of Noturol Sciences ond Engineering,Ljubtjono [Sto]Prof.PhD Marie Kaptanova, Focutty of Chemicot Technology, Pardubice (CZE)Prof.PhD Georgij Petriaszwiti, Worsow University of Techotogy,Worsow (POL)

Doc.PhD Erzsdbet Novotny, Focutty of Light lndustry ond EnvironmentotEngineerin g, Budopest IHUN]Prof.PhD Csaba Horv5th, Focutty of Light lndustry ond Environmentot Engineering,Budopest [HUN]Prof.PhD Stobodan Nedetjkovif , Academy of Arts, Novi Sod [SRB]Prof. Bo5ko Sevo, Acod emg of Arts, Novi Sod ISRBJProf.PhD Katarina Geric, Focutty of Technicol Sciences, Novi Sod [SRB]Prof.PhD Branko Mitosavtjevic, Foculty of Technicol Sciences, Novi Sod ISRBJProf.PhD Sini5a Kuzmanovif, Focu\ty of Technicot Sciences, Novi Sod ISRBJPhD Rossitza Velkova, Printing Industry Union of Butgorio, Sofio (BUL)Doc.PhD Igor Kartovic, Foculty of Technicot Sciences, Novi Sod [SRB]Prof.PhD Rafael Huertas, Deportment of Optics, Focutty of Science,University of Gronodo [ESP]Prof.PhD MiLo5 Sorak, Technicol Focu[ty, Banja Luka IBIHJProf.PhD Itija Cosic, Focutty of Technicot Sciences, Novi Sod ISRB

ORGANIZATIONAL COMMITTEE

President, Igor Kartovic, Focu{ty of Technicol Sciences, Novi Sod [SRB]Dragol.jub Novakovic, Foculty of Technicol Sciences, Novi Sod ISRBJZivko Pavl.ovic, Foculty of Technico[ Sciences, Novi Sod ISRBJZeLjkoZeljkovic, Focutty of Technicot Sciences, Novi Sod ISRB]Sandra Dedijer, Focutty of Technicol Sciences, Novi Sod [SRB]Magdotna Pat, Foculty of Technicot Sciences, Novi Sod ISRB]Nemanja Kaiikovic, Foculty of Technicol Sciences, Novi Sod ISRBJUro5 Nedetjkovic, Foculty of Technico{ Sciences, Novi Sod [SRB]Ivan Pincjer, Foculty of Technicot Sciences, Novi Sod ISRBJivana Tomic, Focu{ty of Technicol Sciences, Novi Sod ISRBJNeda Mitic, Focutty of Technicol Sciences, Novi Sod [SRB]Vl.adimir Zorif, Focutty of Technicot Sciences, Novi Sod ISRBJSrdan Draganov, Focutty of Technicol Sciences, Novi Sod ISRBJGojko Vl.adic, Focutty of Technicol Sciences, Novi Sod ISRBJ

Bojan Banjanin, Focutty of Technicol Sciences, Novi Sod [SRB]

Irma PuSkarevic, rocuity of Technicot Sciences, Novi Sod ISRB)

Rastko MiLo5evii, Focu{ty of Technicol Sciences, Novi^Sod ISRBJ

Jelena Vl.aduiic, Focutty of Technicot Sciences, Novi Sod ISRBJ

Stefan Durdevic, focutiy of Technicol Sciences, Novi Sod [SRB]

Darko Avramovic, Focutty of Technicol Sciences' Novi Sod ISRBJ

Jelena Vtaduiic, Focutty of Technicol Sciences, Novi Sod [SRB]

Jetena Novakovic, foculty of Technicol Sciences, Novi Sod (SRBJ

Marko Brkic, Foculty of iechnicol Sciences, Novi Sod ISRBJ

TECHNICAL SECRETARY

Ivana Jurii, Focu Lty of Technicol Sciences, Novi Sod (SRB]

REVIEWING COMMITTEE

Prof.PhD Mirosalv Gojo, FocuLty of Grophic Arts' Zogreb ICRO]

Prof.PhD Csaba Horvith, facu{ty of Ligirt lndustry ond Environmentol Engineering'

Budopest tHUN)Prof.PhD Diana Gregor - svetec, Focutty of NoturoL sciences ond Engineering'

Ljubtjono [SLo]pror.'pno Tadeja Muck, Focutty of Noturot sciences ond Engineering,

Ljubtjono [SLo]Prof.PhD Marie Kaplanova, Focutty of Chemicol Technotogy' Pardubice ICZE)-

Prof.PhD Dragotjub Novakovic, Focutty of Technicol Sciences' Novi Sod [SRB]

Prof. PhD Rafaet Huertas, Deportment of optics, Focutty of science,

University of Gronodo [ESP]prof.phD Ktementina MoZina, Focutty of Noturot sciences ond Engineering,

Ljubtjono [SLO]Prof. PhD Roz5l,ia Szentgyflrgyvdtgyi, Focutty of Light lndustry ond Environmentol

Engineering,BudoPest, [HU Ni

Doc.phD Igor Kar1ovic, Focutty of Technicol Sciences, Novi Sod [SRB]

Doc.PhD Sandra Dedijer, Focutty of Technicol sciences, Novi sod I$RBJ

O...pnU ZVko Pavtovic. Focuf ty of Technicot Sciences, Novi Sod ISRBJ

Doc.PhD Nemanja Ka5ikovie, Focutty of Technicol Sciences, Novi Sod ISRBJ

Doc.PhD Gojko VLadic, Focutty of Technicot sciences, Novi sod IsRBJ

WITH SUPPORT OF:

Ministry of Education, Science and TechnotogicaI Deve[opment,Republ.ic of Serbia \-

ProvinciaI Secretariat for Science and Technologicat Development,Vojvodina, Repubtic of Serbia

Facutty of Technical Sciences, Novi Sad, Repubtic of Serbia

cEEPUS ill RS-0704-03-1415

CO - ORGANISER:

Facul.ty of Graphic Arls,Zagreb, Croatia6buda University, Institute of Media TechnoLogy, Budapest, Hungary

EOUIPMENT AND MATERIAL DONORS:

KBA, Germany

Atois Carmine KG, Austria

Horizon, Germany

Perfecta, Germany

Ftint Group, Germany

Fo[iant, Czech Repubtic

Da[im Software, Germany

StudioRlP, England

Merus, Stovenia

Rotografika, Subotica, Serbia

Systemic, Betgrade, Serbia

Centropapir, Sremski Karlovci, Serbia

TABLE OF CONTENTS

FOREWORD

INTRODUCTORY LECTURES

l. Huertas R.:

AN OVERVIEW OF RECENT COLOR-DIFFERENCE FORMULAE . . . .I5

2. Novakovic D., Karlovic I., Durdevic S.:

GRAPHICTECHNOLOGIES IN TIMES OF CHANGE .... ".29SPECIAL PRINTING APPLICATIONS AND MATERIALS

3. ViLko 7.,l,gie D., Politis A., Pap K.:,INFRAREDGRAPHIC"@ SECURIry PRINTING TECHNOLOGY

MERGING V AND Z SPECTRUM, . .,

Urbas R., PavLovic 2., Draganov S., Stankovid Etesini U.:

OFFSET PRINTING BY THE MICROCAPSULES _

INFLUENCE ON THE PROPERTIES OF PAPER SUBSTRATE . . . . ' ' .5I

Skola 0., Jairirek 8., VaLiS J., Ndmec P.:

THE STUDY OF POLYMERIZATION OF HYBRID SYSTEMS . .' . . . . 59

Pavtovic 7.,Aedi1er S., Stankovid E.U., Urbas R.:

STRUCTURE OF MICROCAPSULES

ANDIT'SUSEINTHEINDUSTRY-OVERVIEW... .,..".65Cigul.a T., Pavlovic 2.. Fuchs G.R., Risovid D.:

INFLUENCE OF SODIUM METASILICATE SOLUTION'S CHARACTERISTICS

ON THE DEVELOPING OF THE OFFSET PRINTING PLATE .. . . . . . .71

Dedijer S., Pat M.:

COMPARATIVE STUDY OF LINE AND DOT ELEMENTS

REPRODUCTION ON FLEXO PRINTING PLATES USING

DIFFERENTFILM MAKINGTECHNOLOGIES ".....77CiguLa T., Mahovie Potjadek S., Toma5egovie T., Gojo M..

DYNAMIC CONIACT ANGLE AS A METHOD IN

GRAPHIC MATERIALS CHARACTERIZATION ......87DrZkovd M., Pt6dkov5 M.:

EXTENDING THE FUNCTIONALITY OF PRINTED PRODUCTS

USING AUGMENTED REALIry ' ". 93

Dokie M., Kavdid U., Pivar M., Mraovic M., Radonid V., PleterSek A., Muck T.:

PRINTED ANTENNA FOR NEAR FIELD COMMUNICATION TAG.. .......I05Syrovy T., Mitec M., Pretl S., SyrovS 1., Kubersky P.:

PRINTED PRIMARY ZNIMNO2 BATTERIES

FORSMARTPACKAGEAPPLICATION.... ..".'113

Kaiikovic N., Pdt M., MiLo5evie R., Mitie N., JuriSie B.:

INFLUENCE OF TEXTILE WASHING TREATMENT

oN READABILITYOF 0R CODES .. ' '... -ll9Janioviiovi V, Stromajer Z, Krivo5ovS B', Machatov6 Z.:

THE STABILITYOF PRINTED POLYOLEFIN FOILS....... ...... '127

Pan6k O., Hol.ickS H., Hal.enkovic T., Sochovi A., PdcaLtovd A.:

ACCELERATED AGEING OF SAMPLES IMITATING HISTORICAL PRINTS. .... . . . I33

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45

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7.

10.

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Standic M., Grujic D., Ger5ak J.:

INFLUENCE OF PARAMETERS OF DIGITAL PRINIING

ON THERMO- PHYSIOLOGICAL PROPERTIES OF TEXTILE MATERIALS . ...... I39

17. Vukie N., Ristif I., Simendic B, Teofitovie V., Budinski-Simendif J.:

THE INFLUENCE OF AGING ON OPTICAL, MECHANICAL AND

THERMAL PROPERTIES OF PRINTED POLYLACTIDE FILMS. .... ]49

APPLIED MEASUREMENT METHODS IN GRAPHIC ARTS

'l8. Machatov5 2., Jandovidov6 V., Ozimyov5 L.

THE IDENTIFICATION OF HISTORICAL PHOTOGRAPHIC PROCESSES

BYOPTICALMICROSCOPYANDFT-IRSPECTROSCOPY .......I57.l9.

Dvonka V., Reh6kov6 M., eeppan M., Gat 1., BeL6nyiov6 E., Gemeiner P.:

IMAGE ANALYSIS OF WRIIING MEANS AND ITS FORENSIC ANALYSIS . . . . . . . 165

20. Donevski D., Mitidie D., Banie D.:

THE USE OF SHOCK RESPONSE SPECTRUM IN PROTECTIVE PACKAGING . . . . .. . . . . .I7I

2.l. Dvonka V., eeppan M., BeLoviiovS M., Gdt 1., Reh6kov5 M., Gemeiner P.:

GRAPHICAL DOCUMENTS EXAMINATION USING MOLECULAR

SPECTROSCOPYANDCHEMOMETRY... ......I7522. Pil M., Kottai 1., Dedijer S., Draganov S., Dokic M.:

INSTRUMENTAL INVESTIGATION

OF FOLD-CRACK RESISTANCE OF COATED PAPERS ... I83

23. Novotny E.:

EFFECT OF THE APPLICATION OF METAL PRINTING INKS ON

LAMINATION OUALITY OF PLASTIC LAYERS . . . . .I9I

PRINT OUALITY

24. Tsigonias A., Siarampa[ou K., Po[itou G., GamprelLis G., PoLitis A., Tsigonias M.:

HEXACHROME SYSTEM MODIFICATION FOR A PROTOryPE

SCREEN PRINTING REPRODUCTION... ........20325. Majnarif L, Stugic I., Puhato M., Botanca Mirkovic i., MiLo5 A.: .

THE POSSIBILIry OF USING INKJET FOR

PRINTING ON METAL PACKAGING .. .....2II26. Gol.ob G., Ger[ I., Bobnar M., Pivar M.:

COLOUR DIFFERENCES RESULTING FROM DRYING PROCESS OF CONVENTIONAL

PRINTED AND IN-LINE UV VARNISHED CARDBOARD SAMPLES . . . . . . 2I9

27. Bota J., Brozovic M., Hrnjak-Murgif 2,INFLUENCE OF SILICA NANOPARTICLES IN PCL OVERPRINT COATING

ON THE COLOR CHANGE OF OFFSET PRINT . . . .225

28. PLazonie I., Bates I., Barbaric-Mikodevid Z.:

ANALYSIS OF PRINTED DOT FIDELIry ON PAPER SUBSTRATES

MADE OF TRITICALE STRAW FIBRES . . 233

29. RuZidic 8., Standic M., Milo5evif R., SadZakov M.:

INFLUENCE OF SUBSTRATE THICKNESS ON THE REPRODUCTION

OUALITYOFSCREEN-PRINTEDPOLYMERMATERIALS ........23930. Gazibaric 2., Zivkovie P:.

PARAMETERS OF REPRODUCTION AND THEIR INFTUENCE TO

APPEARANCE OF MOIRE PATTERN IN LITHOGRAPHIC OFFSET PRINTING .....247

3.l. MiLo5evic R., KaSikovic N., Standie M., RuZidic B.:

UV LIGHT EXPOSURE EFFECTS ON PRINT MOTTLE OF INK.JET PRINTED

IEXTILE MATERIAL

Kartovii I., Tomii I., Jurid I., Randetovic D.:

DETERMINATION OF SUBSTRATE AND HALFTONE DOT SHAPE INFLUENCE

ON IMAGE REPRODUCTION WITH IMAGE DIFFERENCE METRIC. . . . . . .261

Jurid L, Kartovic I., Tomic L, Zdravkovic S.:

VISUAL EXPFRIENCE OF GRAININESS ...267

SadZakov M., Banjanin 8., RuZidif 8., Adamovid B.:

THE SURFACE COVERAGE ANALYSIS OF METAL SUBSTRATEPRINTED WITH UV INKJET INK... ......273

COLOUR RESEARCH AND APPLICATION

Motek I., Muck T., Javor5ek D.:

WHEREARETHE STANDARDS FOR DIGITAL PROJECTION?... ..-..-. 28I

Vujic J., Agii A., Stanimirovic I.2., Nassirzadeh M.:

THEORY OF TWIN COLORANTS RESPONSE IN VISUALAND INFRARED SPECTRUM.. ...289

SmejkaLov6 H., Dzyk P., VeseLy M.:

LIGHTFASTNESS EVALUATION OF PRINTS USING GAMUT VOLUME ANDVOLGA SOFTWARE ......295HLadnik A., Muck T., PaLanjuk I.:

CLASSIFICATION AND CLUSTERING: TWO MACHINE LEARNING T00LSFOR COLOR IMAGE SEGMENTATION. ...30ITomid I., Huertas R., Jurid I.:

COLOUR TO TEXTURE FUSION IN HSI COLOUR SPACE. . . . . . . .309

Mitie N., Novakovii D., Ka5ikovie N., Dedijer S.:

THE INFLUENCE OF VIEWING CONDITIONS ON COLOUR GAMUT

OFRED-GREENVISION DEFICIENCIES..... ....3I7PRINT MANAGEMENT AND SIMULATION

KoLtai 1., Horvdth C.:

PRINCIPAL OUESTIONS OF THE FUTURES PRINTING SALES ...327

Ribeiro A. de S., Souto P., Mihorko B.:

MISTOOLSTOINCREASESUSTAINABILIry. ......33IZeLjkovic 2., Novakovic D., Avramovic D., Durdevie S.:

THE DEVELOPMENT OF KNOWLEDGE BASE SYSTEM FOR THE IDENTIFICATION

OF THE PARAMETERS OF THE PRINTING PROCESS . . . .335

ENVIRONMENTAL PROTECTION IN GRAPHIC ARTS

Szentgydrgyvtitgy R., AngeLi E.:

CELLULOSE BASED CARTONBOARD ESTER RETENTION. ... ...343

Vukoje M., Pl.azonic I., Barbaric-Mikoievie Z.:

EFFLUENT CHARACTERISTICS FROM NEWSPAPER

CHEMICALFLOTATIONDEINKING. ......351Beielif-Tomin M., Kerkez 0., Prica M., Dalmacija 8., Toma5evii D., Pucar G.:

APPLICATION OF BENTONITE BASED FENTON CAIALYST

lN THE PR0CESS OF REACTIVE DYE DEGRADATION .. .......357

253

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33.

34.

35.

36.

37.

38.

39.

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41.

42.

43.

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47. Simendid 8., Marinkovic V., TeofiLovif V., Vuki6 N.:

THE AMOUNTS AND PROPERTIES OF DUSIRELEASED FROM LASER PRINTERS ......363

48. KerkezD., BedeLic-Tomin M., Prica M., Tomalevif D., Pucar G., Datmacija B.,

Ronievif S.:

DECOLOURIZATION OF REACTIVE RED I2O BY AN ADVANCED

FENTON PROCESS IN CONJUNCTION WITH ULTRASOUND.... .......369

49. Adamovic S., Prica M., Radonif J., Turk Sekul.ic M., Adamovic D., Maletic S..

THE LEACHING OF ZINC FROM PRINTED GRAPHIC PRODUCT WASTE. . . . . . . .375

DIGITAL AND WEB MEDIA

50. GabrijeLeif Tomec H., BratuZ N., Javor5ek D., Javor5ek A.:

COMPARISON OF IMAGE PROCESSING OPERATIONS FOR ADJUSTMENT

AND EVALUATION OF RENDERINGS GENERATED WITH DIFFERENT

RENDERING ENGINES. ... 38I

51. Pincer I., Nedel.jkovid S., Puikarevid I., ZeL)kovie 7..

GRAPHICAL SYSTEM VISUALIZATION IN A VIRTUAL SPATIAL

ENVIRONMENTAS A LEARNING METHOD .....389

52. BratuZ N., Jerman T., GabrUeleie Tomc, H. Javor5ek D..

INFLUENCE OF RENDERING ENGINES ON COLOUR REPRODUCTION. . . . . .395

53. Durdevi e 5., ZeLikovie 2:

THE INTEGRATION OF TTI SENSOR OF SMART PACKAGING

AND MODERN PERSONALPORTABLE DEVICES .......40'I54. Avramovic D., Vl.adic G.:

ANALYSIS OF THE MESSAGE TRANSPORT SYSTEMS

IN AJAX APPLICATIONS USING IMAGES .... .. ..4II

DESIGN, TYPOGRAPHY AND USER EXPERIENCE

55. Mandid 1., PoLji-ak A., Strgar Kuredid M.:

THE USE OF COLOR IN VISUAL PRODUCT MESSAGE REDESIGN . . . . . .423

56. PuSkarevic I., Nedel.jkovic U., Pincer I.:VISUAL ANALYSIS OF THE TYPEFACE MANAGEMENT IN BRAND IDENTIry . . .427

57. Tamds-Nyitrai C., Hegedfs E.:

LINEWORK ON CONSUMER PACKAGING CAN HELP TO

IMPROVE THE IMAGE OF PORT WNES. . . .435

58. Banjanin 8., NedeLjkovie U.:

COMPARING DIFFERENT LETTER SPACING METHODS

lN SANS-SERIFTYPEFACE DESIGN -...- t+41

59. Pineer L, Nedeljkovic U., Draganov S.:

SUBJECTIVE ANALYSIS OF IMAGE OUALlry: EXPERTS AND NAIVE. - . . . . ' 449

60. Mandic 1., Trojko D., Pibernik J., Dolic J.:

THE INFLUENCE OF COLOR IN DIGITAL MEDIA IN USER EXPERIENCE. . . . . . .457

6.l. Vtadif G., Avramovid D., SadZakov M., Mitie N., Kecman M.:

THE INFLUENCE OF PACKAGING SHAPE ON PERCEIVED

PRODUCTVALUEANDCONSUMER NICHE .....46I62. Kuzmanovic 5., VLadic G., Rackov M.:

NEW AND CREATIVE PRODUCT IDEA GENERATION, ASSOCIATION METHOD. . . . . . . .467

63. Rajdetic Z.:

ECONOMIC DESIGN OF VO.JVODINA [.1945-.1985]: INTRODUCTION TO THE ONE STUDY 473

Professional paper

THE POSSIBILITY OF USING INKJET FOR PRINTING ON METAL PACKAGING

Igor Majnarić1, Ana Slugić1, Mateja Puhalo1, Ivana Bolanča Mirković1, Slaven Miloš2,

1 University of Zagreb Faculty of Graphic Arts, Zagreb, Croatia 2MGK-Pack, Rijeka, Croatia

Abstract: Printed packaging surely is the most perspective field of graphic technology. Packaging

is the crucial part of the good placement of products on the market, while constant competition increment makes it even more important. Even though paper is the uppermost material used for packaging production, there are some products (meat products, beverages, fluids…) that demand materials of greater resistance and firmness, like metals. Traditionally, metal packaging is printed in offset printing technique, but digital Inkjet techniques that use UV curing systems also have the possibility to print on any material, accordingly also metals. This enables personalization of metal packaging, short runs and more relevant proof sheet printing. The possibility of Inkjet printing on the steel tin plates (that are normally used for offset printing) will be analyzed in this paper. The aim of the experiment is to determine the successfulness of color printing in Inkjet printing technique onto metals and the possible usage of it for the proof sheets printing. The efficacy of the reproduction of UV LED Inkjet inks on the metal substrate will also be determined. To define every relevant printing parameter (gamut, CIE L*a*b* values, ∆E, ∆L, ∆C, ∆H) and

quality of reproduction of the smallest screen dots, colorimetric and imaging analysis were applied. For the printing of samples on the metal and paper substrate, Roland VersaUV LEC-300 machine was used, applying ECO-UV CMYK colors and UV curing system. Measurements were done by spectrophotometer and colorimeter X-Rite DTP20 Pulse. Results have shown there is a possibility of printing on metal substrates using Inkjet. Average color differences of CMYK patches, between metal and paper substrate, suggest that cyan (∆EC;metal-paper,avg.=4,50) and black (∆EK;metal-paper,avg.=4,63) give the best reproductions. Magenta and yellow show somewhat higher

color differences between metal and paper substrate, which is caused by the lower lightness of the metal substrate itself (∆EM;metal-paper,avg.=6,57; ∆EM;metal-paper,avg.=5,61). Reproductions of dark hues

and solid colors are especially good. Light hues and low halftone values should be avoided or corresponding corrections should be made before printing.

Key words: metal packaging, UV Inkjet printing, proof sheet printing

1. INTRODUCTION

The quality of the printing technique is measured by the quality of the image and hue reproduction. The aim of this paper is to determine both successfulness of reproduction of basic process colors on the metal substrate and their deviations in regard to the reference paper substrate. Accordingly, intention is to appoint the possibility of metal packaging printing with the

usage of Inkjet printing technique. When developing new metal packaging, proof sheets are often printed on inadequate substrates like paper or cardboard. Therefore, obtained prints and results cannot be relevant. It would be suitable to use Inkjet printers instead and print on the metal substrate itself, since they are affordable, compact and intended for short runs and in the same time can print on almost all types of media. Hence, the possibility of Inkjet usage for the needs of metal packaging proof sheets printing will also be researched in this paper. The main characteristic of Inkjet printing techniques is the formation of the liquid ink droplets on the nozzles, which are then being ejected onto the substrate, generating desired content (Cameron, 2005). There are two basic principles of Inkjet technology: continuous and drop on demand (DOD) Inkjet. In this experiment, DOD-principle based technique is going to be used, specifically, piezo Inkjet. In DOD printing systems, a single drop of liquid ink is being formed only when it is needed. This way there is no need to dispose waste ink, because there is no any of it. All DOD Inkjet systems use digital image impulse is order to initiate ink droplet generation (Cameron, 2005). Piezo Inkjet systems use deformation of nozzle micro chamber (therefore, the variation of its volume) in order to generate and eject ink droplet. The piezo-cheramic element that is located in the micro chamber makes this possible, because it changes its shape when affected by electrical charge (Kipphan, 2001). The reduction of the micro chamber volume causes ink meniscus formulation at the opening of the nozzle, which is being ejected onto the substrate when the

micro chamber returns to its primarily shape. Due to fully impermeable substrate, printing on metals is one of the most complex printing processes. To bypass the impermeability of the substrate, special inks that dry instantly are used. Last few years UV-curing inks, that dry immediately when being exposed to UV electromagnetic radiation, are being used. The aim is to replace standard UV mercury vapor lamps,due to their great energy consumption,with more economic LED light sources. In the experiment of this paper, UV-curing inks adapted for piezo Inkjet technique were used (Magdassi, 2010; Page, 2006).The thickness of the printed ink layer in Inkjet can amount up to 15 µm (in multicolor print even 20 µm), meaning UV curing must be conducted at high radiation energies, in order to successfully dry such thick ink layer. The reason of thick ink layer lays in the minimal amount of photoinitiators needed to start the drying process. When drying UV-curing inks, the combination of all three UV spectrum fields (UVA, UVB and UVC) are usually used (first dryer is made of lamps that emit longwave UV radiation, that provides good adhesion of the ink onto the substrate; lamps of the second dryer emit shortwave UV radiation, that dries the surface area of the ink layer). The speed of the print depends on the frequency of ink droplets ejection. Whereas ejection frequency amounts mostly between 5 and 40 kHz, the speed of the print itself also cannot be high and wears up to 0,5 m/s (Kokot, 2007).

2. METHODS

For the needs of the experiment, two types of substrate were used – metal substrate (coated

white tin, 0,27 µm thick) and paper substrate (EMBLEM Solvent Perfect Poster 150, white coated

150 g/m2 paper). The samples were printed with piezo Inkjet printer Roland VersaUV LEC-300.

Printer uses ECO-UV inks and, in accordance with our experiment, four process inks (CMYK) were printed. Inks are UV-curable, for which purpose printerhas two UV LED lamps. Before printing,

linearization of the tone reproduction curve was made, using the spectrophotometer X-Rite

DTP20 Pulse and RIP software VersaWorks. Settings of the RIP software used for the print of

the samples were identical for both substrates: Print quality: high; CMYK; Halftone: dihter;

Direction: uni-direction. On both substrates the same plate (with MonacoProfile pre-defined 378

color patches) was printed. Colorimetric values of the 378 color patches on the samples were

measured with spectrophotometer X-Rite DTP20 Pulse. Measured data were represented as

L*a*b* values showed in software ColorShopX and saved as text file (.txt). Text files were

imported to the MonacoProfiler software, whereby ICC profiles for each substrate were generated

and converted to the visual gamut space with Monaco Gamut Works software.

Text file with the results of the colorimetric measurement was also imported toMicrosoft Office

Excel, where L*a*b* values of cyan, magenta, yellow (25, 50, 70 i 100% HV) and black (33, 66 i 100% HV) were extracted. They were used for the calculation of differences in color (ΔE), lightness (ΔL) and chroma (ΔC) between two substrates. Thereat mathematical formula ΔE2000

was used, defined as:

(1)

For the needs of image analysis, samples were captured with DinoLite camera, while magnified

by Leica DM2500 microscope (magnification of 50x). Personal IAS device was used to measure

the areas of singular dot elements (whereby areas of 5% HV of CMYK patches were measured).

3. RESULTS AND DISCUSSION

3.1 Gamut

The color gamut of the tone reproduction is defined as volume of the three-dimensional CIE L*a*b* space that displays the range of reproduced colors. Figure 1 shows color gamut of measured samples, whereat two different substrates printed with same printing settings (same printer, same UV-curing ink, same content printed, same RIP-settings) are being compared. Thereby the analysis of the substrate impact to the color range reproduction was made possible.

Figure 1: Comparison of the color gamut for two substrates – metal and paper

a) 3D view b) section L=30 c) section L=50 d) section L=70.

The relation of the gamuts in the CIE L*a*b* space and their volumes can be seen on the Figure 1a. Difference between gamut volumes is ∆Vmetal-paper=239,232 volume units. Metal has obviously

smaller gamut volume than paper, mostly as a consequence of light tones not being reproduced (what is also proved on gamut intersections at L=30, L=50 and L=70). On the other hand, darker tones are well reproduced (Figure 1b, intersection L=30) and in that area metal does not deviate significantly in relation to paper. In middle tone areas (Figure 1c, intersection L=50), in relation to

paper, metal shows notable gamut decrease in both directions of a* axis (green and red tone

areas). Metal substrate gamut in light tones area (Figure 1d, intersection L=70) is considerably smaller than paper gamut. Deviation is especially remarkable in red and green tones and, to a lesser extent, in blue tones. The cause of such poor light hues reproduction can be explained by the L*a*b* values of the substrates itself (Table 1). Table 1: L*a*b* values of used substrates

L* a* b*

Paper 94,49 0,72 -2,36

Metal 85,46 -0,38 -4,08

It is notable that metal substrate has significantly lower lightness values than paper (∆L*metal-

paper=9,03). Consequently, all colors printed on metal are darker, what lead to good reproduction of dark tones and light tones loss.

3.2 Colorimetric analysis

3.2.1 Color differences ∆E00

In favor of better understanding of the color difference analysis, it is important to recognize optimal values and ∆E tolerances prescribed by the graphic process standards. The most recent

standard for digital print is PSD – ProcessStandard Digital, which is the base of the ISO 15311

(currently in the adoption procedure). According to it, three print quality categories (A, B and C) have been introduced. Depending on the quality category, color differences should not exceed given values:

Quality type A: ∆E*ab ≤ 2,5 for substrate,

∆E*ab ≤ 3,5 for 100% CMYKRGB and 50% CMYK

Quality type B: ∆E*ab ≤ 3,5 for substrate,

∆E*ab ≤ 5,5 for 100% CMYKRGB and 50% CMYK

Quality type C: ∆E*ab ≤ 4,5 for substrate,

∆E*ab ≤ 7,5 for 100% CMYKRGB and 50% CMYK (Kraushaar, 2012)

Color differences (∆E00) of CMYK colors between two substrates can be viewed at Figure 2. Figure

contains four chart groups, of which every single group represents specific halftone value of CMYK patches (100%, 75%, 50% and 25% HV for CMY and 100%, 66% and 33% HV for K).

Figure 2: Color differences, ∆E00, between metal and paper substrate

Color difference between metal and paper substrate is the least notable in solid tone patches. As the halftone value decreases, color difference between substrates increases, which is an evidence of substrate impact on the printed color itself. It is also a point of interest that different colors tend to show different ∆E deviations for particular halftone values. Considering solid tone patches, yellow color manifests the greatest ∆E deviation (∆EY100%;metal-

paper=5,38) and that difference in color stays pretty permanent, regardless to halftone value decrease (∆EY25%;metal-paper=6,13). Cyan shows very small ∆E deviation in solid tone patches (∆EC100%;metal-paper=1,17), but the color difference increases significantly in middle tone patches and culminates in light tones (∆EC25%;metal-paper=6,40). Magenta acts differently. Its color difference between paper and metal in solid tone patches is notable (∆EM100%;metal-paper=4,40), then decreases on 75% HV and increases enormously in light tone patches (∆EM25%;metal-paper=9,48). Magenta’s color

difference in light tones is too high and exceeds all quality category tolerance values. Black color also shows a specific change. While its color difference in dark and light tones is low and meets the highest quality type (∆EK100%;metal-paper=0,36), ∆E in middle tone patch (66% HV) is tremendous (∆EK66%;metal-paper=14,94). In the last chart group color difference between substrates themselves can be seen (∆Emetal-paper=6,08).

3.2.2 CIE L*a*b* values showed in three-dimensional spaces

To figure out the source of color differences, it is needed to generate CIE L*a*b* 3D color diagrams. Figure 3 shows four diagrams, each of them showing diagram from one of the CMYK colors. For easier comparison, diagrams are showed in correspondingly uniformed scales.

Figure 3: CIE L*a*b* values of CMYK patches

The common characteristic for all four colors is uniformed difference with regard to used substrate. Every color has a characteristic color difference curve, whose shape remains consistent no matter of the substrate used. For all colors, compared to paper substrate curve, curve that represents metal substrate is slightly shifted to the negative lightness direction (-L*) and that alteration is the greatest in yellow patches. The cause of the shift can be found in lesser lightness of the metal substrate itself (Table 1). Comparison of the diagrams shows the tendency of different direction of the colorimetric change, depending on the color. As expected, black does not show any chromatic change (its alteration is pointed in lightness direction (L*)). Yellow color slightly changes in lightness and the main of its change lies in chromatic difference. Cyan and magenta have more or less equal change direction and they change both in chroma and lightness. All three chromatic colors (CMY) reveal colorimetric changes towards achromatic centre of CIE L*a*b* space (lesser saturation). When looked closely at each of the four diagrams, it can be noticed that cyan patches with

greater halftone value printed on paper substrate change in –a* and –b* direction (away from

the achromatic centre). That change suggests its greater saturation and can be explained by permeability of the paper substrate that could lead to greater pigment saturation. Diagram that shows magenta patches reveals unevenness of the saturation change, depending on the halftone value change. Unevenness is more significant on the paper substrate curve, where light tones deviate the most and decreases halftone value increases (∆a*M50-25%, paper=38,75; ∆a*M75-50%,paper=7,38; ∆a*M100-75%,paper=1,16). Such change suggest the greater dot gain on dark tone patches, while its

source probably lies in permeability of paper substrate, causing greater pigment saturation and joined screen elements. The greatest impact on color reproduction, metal substrate shows in yellow patches (L*Y100%,paper =86,95; L* Y 25%,paper=93,21). That also explains very small changes of

yellow tones in lightness direction – in lighter tone patches dark metal substrate has higher impact and makes them darker, so they don’t differ in lightness from more saturated, solid

patches. Change of yellow patches in chroma is even and takes place on b* axis, in achromatic center of CIE L*a*b* space. Black color shows the most even tone reproduction curves, regarding substrates used, and its

change straightly occurs on L* axis. Unlike all the other colors, where darker metal substrate

lowered the lightness of printed patches, black color is not impacted by it.

3.2.3 Lightness and chromatic differences (∆L00 and ∆C00)

Figure 4 shows the lightness (∆L00) and chromatic differences (∆C00) of CMYK colors in regard to

two different substrates. Differences in color originate from differences in lightness and chroma. By observing the separate change diagrams for both of them, it can be determined where the changes occurred.

Figure 4: a) Lightness differences, ∆L00, between metal and paper substrate

b) Chromatic differences, ∆C00, between metal and paper substrate

By comparing those two diagrams, it can be concluded that color difference in solid tone patches, that majorly occurred only in magenta and yellow color patches, originated mostly from lightness difference (∆LM100%=3,94; ∆LY100%=4,85). There was also a minor difference in chroma (∆CM100%=1,40; ∆CY100%=1,70).

The similar thing also occurred in middle tone patches. Difference in lightness is significantly higher than chromatic difference in patches of all four colors (especially in black color patch, as it would be expected, since no chromatic pigments are used in black color). In middle tone patches cyan has the greatest chromatic difference of all colors (∆CC75%=3,29).

Interesting shift in differences happens in middle tone patches. Difference in chroma starts to be higher than lightness difference, especially in cyan and magenta patches. In the lightest tone patches (25% HV) magenta (∆LM25%=0,34; ∆CM25%=8,76) and cyan (∆LC25%=1,41; ∆CC25%=6,25) show almost only change in chroma, while yellow shows only lightness difference (∆LY25%=5,52; ∆CY25%=0,59).

3.3 Image analysis

In order to determine the cause of greater color deviations in light tone patches, it is needed to analyze the reproductions of screen elements in the lightest tone patch (due to good visibility and recognition of each screen element, 5% halftone value patch was used). Observed patch was magnified by 50 times using Leica DM 2500 microscope. By the visual evaluation of the microscopic images, obvious difference between substrate surface structures was spotted. Metal substrate shows the cleanest image of the screen elements. Uniformed formulation of the screen elements (with regard to the fact that FM screening was used on these samples, so geometrically regular arrangement of the screen elements can’t be expected) can also be seen on metal substrate.

Cyan 5% HV Magenta 5% HV Yellow 5% HV Black 5% HV

Meta

l su

bst

rate

Paper

subst

rate

Figure 5: Microscopic images of CMYK color patches (5% HV patches) printed on metal and paper

substrate (magnified 50x)

Deviation is notable only in black color patch and its distribution should be increased (so that it would meet corresponding halftone value of the patch). In comparison to the paper substrate, screen elements on the metal substrate have somewhat bigger area (due to impermeability and smoothness of the metal substrate), but their number is higher.

3.4 Screen elements area

Area of the each screen element was measured with Personal IAS device (patches of 5% halftone value and 2.54x2.54 cm selection area were measured). On the selected area, device detects single screen element and measures its area. Given valuables were statistically processed and visualized by the box diagrams. Figure 6 shows the distribution of area valuables for each screen element, for cyan, magenta, yellow and black color, printed on two substrates.

Figure 6: Area of the screen element of CMYK colors printed on paper and metal substrate

In Inkjet printing technique, the size and position of screen elements is depending on the size of formulated ink drops, respectively the surface tension of the liquid ink. Diagrams showed on Figure 6 display the mean of the screen elements area valuables and their distribution. Scattering of screen element area valuables (A) printed on metal substrate is evidently higher in all color patches (apart from black), than the ones printed on paper substrate. By the calculations of average valuables of screen element areas, all colors show tinier screen element reproduction on paper substrate (∆AC;metal-paper=734,15 µm2). This can be explained by the

impermeability and smoothness of metal substrate surface that caused spillage of the ink and therefore the increasement of the area of the screen element itself.

4. CONCLUSIONS

Paper substrate generates better reproduction of the tones, whereas it has greater gamut volume (∆Vmetal-paper=239,232 volume units). Metal substrate shows good reproduction of dark tones, while

light tones reproduction is poor. The range of tone reproduction is decreasing from dark toward light tones, together with tones on the edge of the gamut (saturated light colors). That can be explained by the low lightness of the metal substrate itself (its difference to paper substrate it amounts ∆L*=9.03). For the better reproduction of light tones, the usage of whiter

base ink is suggested. For the metal substrate, the tone reproduction curve, for all four colors, deviate towards darker tones (that deviation is, as expected, the highest in yellow color). In the solid tone patches differences in color (∆E00) for cyan and black color between paper and metal substrate are very low (∆EC100%;metal-paper=1,17; ∆EK100%;metal-paper=0,36) and therefore belong to quality category A. For magenta and yellow those differences are higher (∆EY100%;metal-paper=5,3; ∆EM100%;metal-paper=4,40) and

belong to quality category B. In dark tone patches, the reproduction of black color (66% HV) is the most problematic (∆EK66%;metal-paper=14,49) and doesn’t meet values of any quality category. The cause for that can be found in lightness differences (∆LK66%;metal-paper=14,84) that didn’t occurred due to colorimetric

differences of substrates but impermeability of the metal substrate (it lead to connection of screen elements). Notable deviations in middle darker tones (75% HV) are spotted in yellow color (∆EY75%;metal-paper=5,49) and cyan (∆EC75%;metal-paper=5,39), but those differences meet criteria of quality

category B. Lighter middle tones (CMY 50% HV) reveal notable color differences between substrates for all three colors. The color difference keeps increasing in 25% halftone value patches where it amounts: ∆EM25%;metal-paper=9,48; ∆EC25%;metal-paper=6,40; ∆EY25%;metal-paper=6,13. Black is getting stabilized

at low halftone values and its color difference lies almost in quality category A tolerance borders (∆EK33%;metal-paper=3,21). Light tone patches (25% HV) for cyan and yellow belong to quality category

C, while light tone patches (25% HV) of magenta show too high color differences to meet any of the quality categories. The average values of color differences of CMYK colors between metal and paper substrate suggest that cyan (∆EC;metal-paper;avg.=4,50) and black (∆EK;metal-paper;avg.=4,63) color have the best

reproduction that belongs to quality category B. Magenta and yellow have poorer reproduction and belong to quality category C (∆EM; metal-paper;avg.=6,57; ∆EM;metal-paper;avg.=5,61).

The uniformed formulation of screen elements on the metal substrate was determined by image analysis. Compared to paper substrate, the number of screen elements on metal substrate is lower, but their area is higher (∆AC metal-paper=734,15 µm2). The cause to that can be found in the

smoothness and impermeability of metal substrate. The usage of Inkjet technology for metal packaging printing is possible with color corrections in dark tones and solid areas. The printing of lighter tones is more problematic, whereas focus to better print of base white color is suggested.

5. REFERENCES

[1] CameronN. Luft, “Ink-Jet Printing,” in Coatings Technology Handbook, 3rd ed., no. 25, A. A.

Tracton, Ed. CRC Press, 2005, p. 25; 1–4.

[2] KipphanH., Handbook of print media. Berlin: Springer-Verlag, 2001.

[3] KokotJ., Ed., UV technology - A Practical Guide for all Printing Processes.

Berufsgenossenschaft Druck und Papierverarbeitung, 2007. [4] KraushaarA., “ProcessStandard Digital - Handbook 2012.” Fogra Graphic Technology

Research Association, 2012.

[5] Magdassi, The Hebrew University of Jerusalem, The Chemistry of Inkjet inks. Singapore:

World Scientific Publishing Co. Pte. Ltd., 2010. [6] [6]Page A., “Developments in Radiation Curing Inks.” Pira International Ltd.,

Great Britain, 2006. [7] PuukkoP., IlmonenA., LamminmäkiT., SundqvistS. „UV-inkjet Ink Penetration and Its Effect on

Print Quality Formation and Drying“, Proceedings NIP25 and Digital Fabrication (2009.), pp. 566-569.