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Proceedings8th CONFERENCE ON INFORMATION AND GRAPHIC ARTS TECHNOLOGY
Ljubljana, Slovenia, 7−8 June 2018
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Proceedings8th CONFERENCE ON INFORMATION AND GRAPHIC ARTS TECHNOLOGY
Ljubljana, Slovenia, 7−8 June 2018
Editors: Raša Urbas, Nace Pušnik
Technical editor: Nace Pušnik
Rewiever: Raša Urbas
Authors accept responsibility for the whole paper.
Design, text layout and cover design: Nace Pušnik
Publisher:
In the book of abstracts and proceedings the typeface family Mantika is used, which was designed by Jürgen Weltin.
Electronic edition: 1st e-ed.
URL:https://www.ntf.uni-lj.si/igt/wp-content/uploads/sites/8/2018/06/8_CIGT_Proceedings.pdf
Kataložni zapis o publikaciji (CIP) pripravili v Narodni in univerzitetni knjižnici v LjubljaniCOBISS.SI-ID=295289344ISBN 978-961-6900-24-9 (pdf)
University of Ljubljana Faculty of Natural Sciences and Engineering Department of Textiles, Graphic Arts and Design Chair of Information and Graphic Arts Technology
OrganizerUniversity of Ljubljana,Faculty of Natural Sciences and Engineering,Department of Textiles, Graphic Arts and Design,Chair of Information and Graphic Arts Technology
Under the AuspicesInternational Circle of Educational Institutes of Graphic-Media Technologies and Management
SponsorshipUniversity of Ljubljana,Faculty of Natural Sciences and Engineering,Department of Textiles, Graphic Arts and Design,Chair of Information and Graphic Arts Technology
Organizing committeeConference director• Raša Urbas − University of Ljubljana, SloveniaMembers• Jure Ahtik − University of Ljubljana, Slovenia• Aleš Hladnik − University of Ljubljana, Slovenia• Barbara Luštek Preskar − University of Ljubljana, Slovenia• Klemen Možina − University of Ljubljana, Slovenia• Deja Muck − University of Ljubljana, Sloveni• Nace Pušnik − University of Ljubljana, Slovenia
Programme and review committeeChairman • Aleš Hladnik − University of Ljubljana, SloveniaMembers • Bojana Boh Podgornik − University of Ljubljana, Slovenia• Luk Bouters − Ghent University, Belgium• Sabina Bračko − University of Ljubljana, Slovenia• Helena Grabijelčič − University of Ljubljana, Slovenia• Diana Gregor Svetec − University of Ljubljana, Slovenia• Nemanja Kašiković − University of Novi Sad, Serbia• Branka Lozo − University of Zagreb, Croatia• Sanja Mahovič Poljaček − University of Zagreb, Croatia• Klementina Možina − University of Ljubljana, Slovenia• Deja Muck − University of Ljubljana, Slovenia• Živko Pavlović − University of Novi Sad, Serbia• Nace Pušnik − University of Ljubljana, Slovenia• Dimitrina Todorova − University of Chemical Technology and Metallurgy, Bolgaria• Raša Urbas − University of Ljubljana, Slovenia• Urška Vrabič Brodnjak − University of Ljubljana, Slovenia
Sponsors
8th Conference on Information and Graphic Arts Technology 7
BIOMASS UTILIZATION IN POLYMER SYNTHESIS AND NANOCELLULOSE PRODUCTIONMatjaž KUNAVER1, Ema ŽAGAR1 & Raša URBAS2
1 National Institute of Chemistry, Slovenia2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
COMPUTATION APPROACH FOR REALISATION OF CONTEXT-AWARE ROBOTSTomislav STIPANČIĆ1, Duška ROSENBERG2 & Bojan JEREBIĆ1
1 University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Croatia2 University of London
3D PRINTING FOR DESIGN AND ARTBarbara WILKESMANN HOČEVAR1, Deja MUCK2
1 Chemets d.o.o., Slovenia2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
BIOCOMPOSITE PLA FILAMENT FOR 3D PRINTINGDiana GREGOR-SVETEC, Urška STANKOVIČ ELESINI, Mirjam LESKOVŠEK, Urška VRABIČ BRODNJAK & Raša URBASUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
COLORIMETRIC CHANGES CAUSED BY UV VARNISHINGIvana CAR, Igor MAJNARIĆ & Branka LOZOUniversity of Zagreb, Faculty of Graphic Arts, Croatia
COMPUTER GENERATED HANDWRITING SIMULATION BASED ON ALTERNATION OF CHARACTERS Mihael Aleksander MAHKOVIC, Klementina MOŽINAUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
DEFINING THE OPTIMAL TRAINING SET SIZE FOR CAMERA-BASED COLOUR MEASUREMENT OF GONIOCHROMATIC PRINTS: A PRELIMINARY STUDY Ivana TOMIĆ, Sandra DEDIJER, Dragoljub NOVAKOVIĆ & Ivan PINĆJERUniversity of Novi Sad, Faculty of Technical Sciences, Department of Graphic Engineering and Design, Serbia
DIFFERENCES BETWEEN DESIGNERS’ AND USERS’ PERCEPTION OF INSTRUCTIONS DESIGNDorotea KOVAČEVIĆ, Maja BROZOVIĆUniversity of Zagreb, Faculty of Graphic Arts, Croatia
ELECTRON BEAM CURING OF PRINTING INKS IN PACKAGING INDUSTRY Jakub GRIGER1, Dávid ŠARISKÝ1, Zuzana ŠTROMAJER1, Michal ORAVEC2, Michal ČEPPAN2 & Viera JANČOVIČOVÁ2
1 Chemosvit Fólie, a.s., Slovakia 2 Slovak University of Technology in Bratislava, Faculty of Chemical and Food Technology, Department of Graphic Arts Technology and Applied Photochemistry, Slovakia
Table of contents
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INVITED LECTURES
ORAL PRESENTATIONS
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EQUIPPING THE ARS VIVA INSTITUTE WITH WEB COMMUNICATION CHANNELSAnja ŠKERJANC1, Jure VIDMAR2, Primož PREVC2 & Matija MAROLT3
1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia2 University of Ljubljana, Faculty of Electrical Engineering, Slovenia3 University of Ljubljana, Faculty of Computer and Information Science, Slovenia
EXTAND OF PAPER COATING CRACKINGKlemen MOŽINA1, Jure AHTIK1, Špela BEČAJ1, Urška KRAJNC1, Matej PIVAR1, David RAVNJAK2 & Diana GREGOR SVETEC1
1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia2 B & B, Papirnica Vevče, Labels and Flexpack, Slovenia
FABRICATION OF CAPACITIVE SLIDERS Tanja PLEŠA1, Urška KAVČIČ1, Gregor LAVRIČ1 & Deja MUCK2
1 Pulp and Paper Institute Ljubljana, Slovenia2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
FORMATION AND CHARACTERISATION OF SHELLAC FILMSUrška VRABIČ BRODNJAKUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
MONTE CARLO DENOISING OF COMPUTER GENERATED IMAGES BY NON-LOCAL MEANS FILTERINGHelena GABRIJELČIČ TOMC, Aleš HLADNIKUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
RECONGNITION OF WORDS WITH JUMBLED LETTERSNace PUŠNIK1, Primož WEINGERL1, Vladimir DIMOVSKI2 & Irma PUŠKAREVIĆ2 1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia2 University of Novi Sad, Faculty of Technical Sciences, Department of Graphic Engineering and Design, Serbia
THE DEVELOPMENT OF THE GENERATIVE BRANDS’ CATEGORIZATIONAnže KAVČIČ, Helena GABRIJELČIČ TOMCUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
THE EFFECTS OF TYPEFACE AND IMAGE COMPLEXITY ON CONSUMER' VISUAL ATTENTION AND ATTITUDINAL RESPONSES IN ADVERTISINGIrma PUŠKAREVIĆ1, Uroš NEDELJKOVIĆ1, Ivan PINĆJER1, Gregor FRANKEN2 & Nace PUŠNIK2
1 University of Novi Sad, Faculty of Technical Sciences, Department of Graphic Engineering and Design, Serbia2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
THE INFLUENCE OF BACTERIAL NANOCELLULOSE ADDITION ON MECHANICAL PROPERTIES OF PAPER Gregor LAVRIČ, Igor KARLOVITS, Tanja PLEŠA & Mija SEŽUNPulp and Paper Institute, Ljubljana, Slovenia
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THE POSSIBILITY OF USING ARDUINO BASED WATER LEVEL SENSOR FOR TISSUE PAPER ABSORPTION RATE AND CAPACITY MEASUREMENT Igor KARLOVITS, Urška KAVČIČ, Tanja PLEŠA & Mija SEŽUNPulp and Paper Institute, Ljubljana, Slovenia
USE OF IMAGE SEGMENTATION FOR WOVEN FABRICS’ POROSITY AND ALPHA MAP DETERMINATION Tanja Nuša KOČEVAR, Živa ZUPINUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
USER EXPERIENCE OF WAIT-ANIMATION PROGRESS INDICATORS Jesenka PIBERNIK, Jurica DOLIĆ, Roberta STANIĆ & Lidija MANDIĆUniversity of Zagreb, Faculty of Graphic Arts, Croatia
AVAILABILITY OF E-TEXTBOOKS ON THE SLOVENIAN MARKET Grega TOMAŽIN1, Urška STANKOVIČ ELESINI2
1 University of Ljubljana, Academy of Fine Arts and Design, Slovenia2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
BLUEPRINTING - AN ANCIENT BUT STILL LIVING WAY OF PRINTING TEXTILES Veronika KRAVCOVÁ1, Ondrej PANAK1, Petra FORTE TAVČER2
1 University of Pardubice, Faculty of Chemical Technology, Department of Graphic Arts and Photophysics, Czech Republic2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
COLOUR AND ODOUR PERCEPTION AT COSMETIC PACKAGING Kaja JOKIĆ, Barbara BLAZNIK & Sabina BRAČKOUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
COLOUR OF TASTE Gregor FRANKENUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
COMPARISON OF DIGITAL AND TRANSFER PRINTING OF COTTON FABRIC Michaela ČESÁKOVÁ1, Ondrej PANAK1, Petra Forte TAVČER2
1 University of Pardubice, Faculty of Chemical Technology, Department of Graphic Arts and Photophysics, Czech Republic2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
COMPARISON OF SCREEN PRINTED AND ARDUINO-BASED SENSORS FOR ALCOHOL DETECTION Urška KAVČIČ1, Igor KARLOVITS1 & Matej PIVAR2 1 Pulp and Paper Institute, Ljubljana, Slovenia2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
CREATION OF INTERACTIVE BOARD FOR LEARNING ABOUT TYPOGRAPHYTevž ZRINSKI, Klementina MOŽINA & Dejana JAVORŠEK University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
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POSTER PRESENTATIONS
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DESIGN OF A GIFT CERTIFICATE USING PROTECTIVE ELEMENTS IN A STANDARD TRIADNadezhda SAVCHUK, Olga NOVOSELSKAYAByelarussian State Technological University, Informatics and Web-Design Department, Belarus
DEVELOPMENT OF DISPERSION BARRIER COATING FOR GREASE, MINERAL OIL AND WATER VAPOUR Jelena VASILJEVIĆ1, Barbara GOLJA1, Ivan JERMAN2, Ervin ŠEST2, Matic ŠOBAK2, David RAVNJAK4, Mateja KERT1, Marija GORJANC1, Brigita TOMŠIČ1, Tea KAPUN3, Diana GREGOR-SVETEC1 & Barbara SIMONČIČ1
1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia2 National Institute of Chemistry, Slovenia3 Pulp and Paper Institute, Slovenia4 Paper Mill Vevče d.o.o., Slovenia
ENZYMATIC DEINKING OF FLEXOGRAPHIC PRINTED PAPER Mija SEŽUN1, Gregor LAVRIČ1, Gašper DOKL2 & Matej PIVAR3
1 Pulp and Paper Institute, Ljubljana, Slovenia2 University of Ljubljana, Biotechnical Faculty, Slovenia3 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
EVOLUTION OF NATURAL PATTERNS FROM RANDOM FIELDS Lovrenc ŠVEGL1, Igor GRABEC2 1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia2 University of Ljubljana, Faculty of Mechanical Engineering, Slovenia
EYE TRACKING ANALYSIS OF INTERNAL FACIAL FEATURES IN OBSERVATION AND RECOGNITION PROCESSAndrej ISKRA, Helena GABRIJELČIČ TOMCUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
HOW COLOR SHAPES BRAND IDENTITY Urška STANKOVIČ ELESINI1, Karla MRKOBRADA1 & Jani TOROŠ2
1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia2 Innovative Management Institute Ljubljana, Slovenia
IMPACT OF THE AGE OF THE PIGMENT PRINTING PASTE ON THE PRINT QUALITY Petra FORTE TAVČER University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
INFLUENCE OF OPTICAL PAPER PROPERTIES OF RECYCLED AND NON-RECYCLED PAPERS FOR DIGITAL PRINTING ON COLOUR REPRODUCTIONIvana JURIČ, Dragoljub NOVAKOVIĆ, Nemanja KAŠIKOVIĆ, Sandra DEDIJER & Neda MILIĆUniversity of Novi Sad, Faculty of Technical Sciences, Department of Graphic Engineering and Design, Serbia
POLYLACTIC ACID FIBERS CONTAINING FLUORESCENT PIGMENTSViera JANČOVIČOVÁ, Barbora ĎURICOVÁ, Veronika HRABOVSKÁ & Katarína HABEROVÁ Slovak University of Technology in Bratislava, Faculty of Chemical and Food Technology, Department of Graphic Arts Technology and Applied Photochemistry, Slovakia
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PREVENTION OF STARCH DEGRADATION IN PAPER MAKING PROCESS FOR RECYCLED PACKAGING PAPER Dimitrina TODOROVA, Ventsislav BLYAHOVSKI & Spas LADZHOVUniversity of Chemical Technology and Metallurgy, Bulgaria
PRINTING BRAILLE WITH SPECIAL EXPANDABLE SCREEN PRINTING INKS Karin KUKEC, Raša URBASUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
SCIENTIFIC ILLUSTRATIVE DESIGNS IN GRAPHIC PRODUCTSTadej PREZELJ, Urška VRABIČ BRODNJAKUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
SELECTING THE TRADEMARK COLOUR DEPENDING ON THE COMPANY’S BUSINESS AREA Ivan PINĆJER, Ivana TOMIĆ, Irma PUŠKAREVIĆ & Gojko VLADIĆUniversity of Novi Sad, Faculty of Technical Sciences, Department of Graphic Engineering and Design, Serbia
SELF-FOLDABLE KNITTED BAGS FOR HOUSEHOLD STORAGE OF BAKERY PRODUCTS BASED ON BIOMIMETICSDarja RANT, Alenka PAVKO-ČUDENUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
STUDY OF ACCELERATED AGING OF BLACK INKJET PRINTSMichal ORAVEC, Lukáš GÁL, Michal ČEPPAN & Patrícia PARAČKOVÁ Slovak University of Technology in Bratislava, Faculty of Chemical and Food Technology, Department of Graphic Arts Technology and Applied Photochemistry, Slovakia
STUDY OF CHANGES OF WRITING INKS ON THE PAPER DOCUMENTS Silva STAŠKOVÁ, Milena REHÁKOVÁ & Aleš HÁZSlovak University of Technology in Bratislava, Faculty of Chemical and Food Technology, Institute of Natural and Synthetic Polymers, Slovak Republic
SYNTHESIS, COATING AND EVALUATION OF ANTIMICROBIAL MICROCAPSULES ON PAPERBojana BOH PODGORNIK1, Boštjan ŠUMIGA2, Barbara GOLJA1, Matej ŠUŠTARŠIČ2, Barbara ŠUMIGA2 & David RAVNJAK3
1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia2 Pulp and Paper Institute, Ljubljana, Slovenia3 Papirnica Vevče d. o. o., Slovenia
TLC AND GC/MS ANALYSIS OF INK JET PRINTING INKS Barbara BLAZNIK1, Franci KOVAČ2 & Sabina BRAČKO1
1 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia2 University of Ljubljana, Faculty of Chemistry and Chemical Technology, Slovenia
TYPEFACE AND ECOLOGICAL DESIGN Klementina MOŽINA, Alenka TOMAŠIČUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
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USE OF BIOCOMPOSITE FILAMENTS FOR 3D PRINTING Maruša ROPRET, Helena GABRIJELČIČ TOMC & Deja MUCKUniversity of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
USING UAV RGB CAMERA AS A COLOUR MEASURING DEVICE Andrej UČAKAR, Aleš HLADNIK University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Slovenia
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COLORIMETRIC CHANGES CAUSED BY UV VARNISHING
Ivana CAR, Igor MAJNARIĆ & Branka LOZOUniversity of Zagreb, Faculty of Graphic Arts
ABSTRACT: This paper examines the influence of UV LED varnish on color change of varnished substrates. In-dustrially manufactured dyed papers in 8 different colors (green, red, blue, cyan, yellow, brown, black and light yellow) were UV varnished on Roland VersaUV LEC-300 printing machine in UV LED Inkjet printing technique. Each sample of dyed papers was varnished in four different surface coverage in half-ton values of 20%, 40%, 60% and 80%. Varnished papers were submitted to colorimetric analyses using X-Rite eXact spectrophotome-ter. From the obtained L*a*b* values, the difference in coloration (ΔE2000) was calculated by CIE Lab ΔE2000 equation. The results of the colorimetric analyses were presented in the form of three-dimensional CIE Lab diagrams showing the color changes in brightness and chromaticity. Color change ΔE2000< 1 is considered visually unnoticeable in contrast to color change ΔE2000> 1 that is visually noticeable. Above the color change, some samples showed significant change in chromaticity.
Keywords: color change, UV varnish, half-ton value, dyed papers.
1 INTRODUCTION
Paper, as the most important carrier of information in the past, has expanded its application. A large variety of paper grades are produced to suit the special requirements. Paper can be impregnated, coated, laminated, creped, molded etc (Holik, 2006.). One of the methods used for applying the impregnated layers on the surface of the paper is UV Inkjet printing technology. In this technology, the transparent UV LED varnish in liquid form is directly applied on the printing substrate and it is cured by LED UV light (Majnarić, 2012.). This paper analyze how different surface coverage of the transparent UV LED varnish applied by UV Inkjet printing technology influence on color change of varnished substrates. Varnished substrates used in the experiment are industrially manufactured dyed papers in 8 different colors (green, red, blue, cyan, yellow, brown, black and light yellow). Generally, materials are colored by the use of pigments or dyes that differ in their application. When a pig-ment is used to color substrate, the finely divided, insoluble solid remains throughout the coloration process (Lewis, 2006.). Dyes, in the other hand, penetrates the substrate in soluble form, after which it may or may not become insoluble (Vernardakis, 2006). By the Herbert Holik’s book »Handbook of Paper and Board«, dyes are the oldest class of synthetic specialty chemicals employed in the production of paper. Anionic direct dyes are the dominant class of dyes which ac-count for 52 % of the total worldwide turnover. Anionic direct dyes are the sodium salts of azo dyes containing sulfo groups (for water solubility) or copper phthalocyanines which also contain sulfo groups. They have a high affinity to bleached chemical pulps and often do not need additional fixing agents. The colors attainable may not be as brilliant as with acid and basic dyes but the lightfastness is usually adequate. Basic dyes are the salts (chlorides, hydrochlorides, sulfates, and oxalates) of color bases. Although they are tinctorially strong, basic dyes have poor affinity to bleached furnishes, besides theirs mottling tendency and poor lightfastness. Acid dyes are all water-soluble salts of colored organic acids which dissociate in water to form colored ani-ons. They have little affinity to paper fibers. Cationic direct dyes retain the planar molecular structure of acid direct dyes. Cationic groups, incorporated in the structure, accelerate their affinity to paper fibers. They are moderately adsorbed on bleached lignin-containing stocks and produce fairly good bleed fastness. Fixative is usually not required for these dyes. For the most efficient usage, the dyes are mostly added continuously and fully automatically into the stock flow. Stock or internal dyeing is the most widely used paper dyeing process. The choice of dyeing conditions largely depend on the raw materials used in papermaking (recycled fibers, stone groundwood, TMP, CTMP, unbleached or bleached chemical pulp, type and portion of filler) and on its preparation process e.g. a higher degree of beating of the pulp results in a deeper coloring (Holik, 2006.).
The pH conditions are very important in stock dyeing and have tendentious toward paper production in the neutral or alkaline pH range. These conditions need dyes with a very good affinity to the paper stock in a neutral medium and/or very effective fixatives and retention aids.
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Batch addition, as one of the stock dyeing processes, involve thorough mixing of the additives with the paper stock which increase optimal fixation due to longer contact time between the fiber and dye. In the other hand, the time required for color correction and color change is relatively long.Continuous addition can attain the desired shade more quickly but have a lower color yield for intensely colored papers (Holik, 2006.).
2 EXPERIMENTAL
Four types of digitalized printing forms with surface coverage in 20%, 40%, 60% and 80% of half-ton values were constructed for the needs of experiment. They were used for LED UV varnishing of industrially manufactured dyed papers in 8 different colors (green, red, blue, brown, cyan, black, yellow and light yellow) in four different surface coverage. Each standard printing substrate used in the experiment had a slight difference in weight (gmin= 112,45 g/m2 for blue dyed substrate, gmax= 121,05 g/m2 for green dyed substrate).LED UV varnish was applied on the surface of industrially manufactured papers by LED UV printer Roland VersaUV LEC 300 in UV LED Inkjet printing technique.By UV printing of felt side (FS) four characteristic samples were made: prints with the surface coverage of 20%, prints with the surface coverage of 40%, prints with the surface coverage of 60% and the prints with the surface coverage of 80%. Varnished and not varnished papers were submitted to colorimetric analyses using spectrophotometer model X-Rite eXact Advanced (mode M1, light condition D50, standard observer 2°). Measurements were made on 10 randomly chosen samples.Program x-Rite Datachatcher were used for calculating output results such as CIE L*a*b*, c*, H*, x, y, Y, and spectral reflection in the visible part of the spectrum. All values were measured three times and average val-ues were used for further analysis. From the obtained L*a*b* values, the difference in coloration (ΔE2000) was calculated by CIE Lab ΔE2000 equation. The results of the colorimetric analyses were presented in the form of three-dimensional CIE Lab diagrams showing the color changes in lightness and chromaticity. Color change ΔE2000< 1 is considered visually unnoticeable in contrast to color change ΔE2000> 1 that is visually noticeable. Above the color change, some samples showed significant change in chromaticity.
Figure 1. Schematic presentation of the performed experiment.
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3 RESULTS & DISCUSSION
In this work the analysis is directed to LED UV Inkjet printing technique which enables the coating of transpar-ent LED UV varnish which can result in color change on the surface of printing substrates, besides the visual effect of gloss. The color change is not the same for all dyed substrates neither is equal for the same amount of applied varnish (Dolić, 2014.). Based on the measurements, the results showed that for some dyed substrates (i.e. for green) varnished by 20% half-ton coverage the color change is remarkably smaller (ΔE0-20%= 1,42) than for 40% varnish coverage (ΔE0-40%= 21,06) (Figure 2). Red and blue dyed substrates showed the linear color change for subsequent increase of varnish coverage. For a minimum varnish coverage of 20%, the color change was barely visible (ΔE0-20%= 1.07-1.09) for both samples. For the maximum varnish coverage of 80% color change was visible (ΔE0-80%= 4.69). On 3D and 2D graphs the color change of three differenty dyed substrates (green, red and blue) is presented. Each color change is the result of 4 different ways of LED UV varnishing (varnish coverage of 20 %, 40 %, 60% and 80 % half-ton value) and all the differences in color change are compared with the unvarnished samples.
Figure 2. Color changes of red, blue and green dyed substrates caused by UV LED varnishing with the differ-ent surface coverage in half-ton values of 20%, 40%, 60% and 80%: a) 3D diagram of dyed substrates, b) 2D
diagram of dyed substrates.
The brightest colored substrate (light yellow) showed low but slightly visible color change with the maxi-mum varnish coverage of ΔEmax= 3.96 (Figure 3). The black sample was the only one to keep the color change at low level (ΔE0-80%= 1,39) for the maximum varnish surface coverage of 80% half-ton value. The common characteristic of both substrates (black and light yellow) is that minimum varnish coverage of 20% half-ton value is almost undetecteble.
Figure 3. Color changes of brown, light yellow and black dyed substrates caused by UV LED varnishing with
the different surface coverage in half-ton values of 20%, 40%, 60% and 80%: a) 3D diagram of dyed sub-strates, b) 2D diagram of dyed substrates.
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Same samples (brown and cyan) showed a change in chromaticity for different surface coverage of UV var-nish (Figure 4). Besides the visible color change at 20% of the surface coverage (ΔE0-20%= 1.55), brown colored substrate also showed the color change of the tone (chromaticity) with tendency in direction of -b coordi-nate (blue). The largest change is noticeable between 40% and 60% of the surface coverage.Cyan colored substrate showed the linear color change for subsequent increase of varnish coverage (ΔEmax= 6.65), but its color change is already visible with minimum varnish coverage of 20% half-ton value (ΔE0-20%= 1.55). Cyan also showed the color change of the tone with tendency in direction of +a coordinate (red).
Figure 4. Color changes of yellow and cyan dyed substrates caused by UV LED varnishing with the differ-
ent surface coverage in half-ton values of 20%, 40%, 60% and 80%: a) 3D diagram of dyed substrates, b) 2D diagram of dyed substrates.
4 CONCLUSIONS
By application of UV varnish on industrially manufactured dyed papers most samples showed visible color change (ΔE> 1) for varnish coverage of 80% half-ton value. Such effects are undesirable and could be adjusted for each sample by application of lower surface coverage (20%, 40% or 60%) of UV varnish. The green sample showed the highest color change visible in 40%, 60%, and 80% of surface varnish coverage and is thus considered unsuitable for LED UV varnishing. On the other side, all three samples (red, blue and cyan) with the linear color change showed barely visible color change for a minimum varnish coverage of 20% (ΔE0-20%= 1,07-1,55). For the maximum varnish coverage of 80%, color change was noticeable (ΔE0-80%> 4,5) and also unsuitable for LED UV varnishing in all three cases. The black sample showed the slightest color change, barely visible even with application of maximum surface coverage of 80% of UV varnish. It is thus considered to be the most suitable for LED UV varnishing applications. Visible color change of some UV varnished samples can be also used to provide additional aesthetic effect.
5 REFERENCES
• Holik, H. (Ed.), 2006. Handbook of Paper and Board. Weinheim: WILEY-VCH Verlag GmbH & Co. KGaA • Majnarić, I., Bolanča Mirković, I., Golubović, K., 2012. „Influence of UV curing varnish coating on surface
properties of paper“ Paper presented at the Tehnički Vjesnik-Technical Gazette (1330-3651) 19 (2012), 1; 51-56• Lewis, A. P., 2006. „Colored Inorganic Pigments“ In Book Coatings Technology Handbook, Third Edition,
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Corresponding author:Ivana CAR University of Zagreb, Faculty of Graphic Arts, Department of Materials in Graphic TechnologyGetaldićeva 2, 10 000, Zagreb, Croatiaphone: +385 95 544 47 83, e-mail: [email protected]
8th Conference on Information and Graphic Arts Technology 41
Oral presentations
Co-author(s):Igor MAJNARIĆ University of Zagreb, Faculty of Graphic Arts, Department of PrintingGetaldićeva 2, 10 000, Zagreb, Croatiaphone:+385 91 288 20 29, e-mail: [email protected]
Branka LOZOUniversity of Zagreb, Faculty of Graphic Arts, Department of PrintingGetaldićeva 2, 10 000, Zagreb, Croatiaphone: +385 98 480 864, e-mail: [email protected]