Development of the model for production efficiency increase and functionality of packaging

Graphic technology is a part of technical sciences which implements research advances in the various fields including computer science and material sciences. This fact leads to a specific approach to the research as one must always have in mind the two way communication between image data manipulation in the digital and materials interaction in the printing process and product finishing. The aim of this research proposal is to develop the model for production efficiency increase and functionality of packaging. This goal will be achieved by conducting the activities which could be divided in four main groups:
  • development and evaluation of the grey colour replacement (GCR) method
  • development of the method for implementing digital watermark as a mean to enable graphic reproduction protection
  • characterization of graphic materials and development of functional coatings and their impact on the multicolour graphic reproduction
  • development and evaluation of the mathematical model which will make connection between influence of the digital image modulation and material's characteristics and prints refining on it's mechanical properties and visual perception.
Majority of the young scientists find it challenging to come out of the shadow of their senior colleagues. This project supported by Croatian Science Foundation gave us the opportunity to work as a team of young researchers. As a group of researchers which come from various expertise it is exciting to collaborate, see different views and approaches to the same problem. We see the challenges lying in front of us and are sure that crossing the obstacles will bring every team member forward on a path of scientific life and in the same time form a multidisciplinary research force able to challenge issues in the graphic materials and, especially, packaging production.
Beside personal motives, as a part of the graphic communications/printing industry, we expect to reach the main goals of the project - increase of the packaging production competitiveness and increase packaging functionality by implementing protecting elements in the image and material refinement to increase its mechanical properties and visual perception.

M.E.G.A. Webinar

The webinar will present the project Development of the model for production efficiency increase and functionality of packaging as well as showcase the results achieved so for. Webinar, set for Thursday, February, 4th 2021, will have the following schedule. 9.45 –10.00 registration (zoom – https://rit.zoom.us/j/97582276073, Meeting ID: 975 8227 6073) 10.00 –10.15 Introduction – Short […]


The members of the project attended the International Symposium on Graphic Engineering and Design – GRID20. The objective of GRID is connecting researchers from industry and institutions related to the field of graphic engineering and design through presentation of research results to scientific and professional community. Two papers were presented on the conference: PCL-TIO2 NANOCOMPOSITE […]


The team members of M.E.G.A. Tamara Tomašegović and Tomislav Hudika are attending NANOSMAT2020 conference. Due to the epidemiologic measures, the conference will be held virtually by presenting the papers as video recordings. Two topics will be presented: Properties of protective PCL paper primers with SiO2 and ZnO nanoparticles for application in offset printing te PCL/TiO2 […]

61st International Symposium ELMAR-2019, Zadar

For the 61st time, Zadar was the host of ELMAR symposium – an international conference that covers multiple fields of science, such as Wireless Communication, Computer Vision, Robotics, etc. The symposium was held in Falkensteiner Club, Zadar, from September 23rd to September 25th. Two MEGA team members presented research papers (both can be found in […]
Project Leader
"Valid criticism does you a favor."
by Carl Sagan
Junior Researcher
Senior Researcher
Learning curve ranger with one and a half foot on the ground
Junior Researcher
Jack of several trades, trying to master at least one
Senior Researcher
Senior Researcher
"As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality."
by Albert Einstein
Senior Researcher

Lightfastness, surface and interfacial properties of colour-printed paper substrates coated with PCL/ZnO and PCL/TiO2 nanocomposites

Packaging production often includes varnishing to increase printed information durability. In addition, as some materials cannot be recycled (which could be the case in food packaging), the use of biobased materials enables waste to be composted. This paper proposes biopolymer-based nanocomposite coating which could be applied onto the printed paper substrate to protect it and increase its barrier properties to the water vapour. For the purpose of the research, two sets of the nanocomposite coatings were prepared by mixing polycaprolactone (PCL) base with ZnO or TiO2 nanoparticles in different weight concentrations. The prepared nanocomposites were applied onto the printed samples and artifi...

Color reproduction on varnished cardboard packaging by using lower ink coverages due to the gray component replacement image processing

Even in these challenging times, cardboard packaging industry is increasing its revenue with stable annual increase prediction, but customers are increasing demands on the packaging with respect to environmental protection, attractiveness, and branding. This article aims to determine the influence of image processing in terms of gray component replacement and overprint varnishing on the color reproduction on a cardboard packaging material. A test chart with tertiary colors was defined and modified by different gray component replacement levels. It was printed in accordance with ISO norm on coated and uncoated cardboard and finished by overprinting water based, offset, and UV varnish. The pre...

PCL-TIO2 Nanocomposite to Improve Ageing of Offset Prints

UV radiation or sunlight can affectthe printed sample by fading the ink surface and therefore the product losses it's decorative purpose and becomes less desirable to the customer. To create the efficient protective coating,titaniumdioxide(TiO2)will be used as a well-knowncompound that should lower the effects of UV radiation. TiO2should lower the colour fade after UV radiation and this will be determined by densitometric and colorimetric (CIE L*a*b*)measurements. In addition, measurement of print gloss will also be conducted to evaluate visual appearance of the sample. Biopolymer Polycaprolactone (PCL) wast...

The Influence of PCL-ZNO Coating Composition on Coated Offset Cardboard Prints

The most significant printing branch in these days is packaging printing. Packaging must primarily preserve the product from damaging, but atthe same time must attract the consumersto be picked up from the shelf in the store. To ensure protective and aesthetic role of the packaging the prints are commonly coated with varnishes which will improve visual, mechanical, surface, and optical properties. In this paper a coating composed of polycaprolactone (PCL) and nanoscale ZnOwas used to coat the offset prints on the cardboard. The coatingswereprepared by adding various weight amounts of the ZnO nanoparticles (weight ratios of 0.1, 0.5 and 1%) into the mixture of PCL and ethyl-acetate. The coati...

Influence on the properties of cyan and magenta offset prints

Polycaprolactone primers with zinc oxide and silicon dioxide nanoparticles for paper substrates: Influence on the properties of cyan and magenta offset prints   In this research study, the applicability of polycaprolactone‐silicon dioxide and polycaprolactone‐zinc oxide coatings used as primers on papers for offset printing, was analysed. Polycaprolactone nanocomposites with different concentrations of nanoparticles were prepared […]...

Effect of the paper surface properties on the ink transfer parameters in offset printing

Paper has a crucial impact on the qualitative properties of printed product as properties of the paper’s surface directly impact the ink transfer, consequently, basic optical properties of the print. Although same ISO paper type, papers possess variable surface properties leading to different influence on the ink transfer. The aim of this research was to analyse influence of the surface properties of the paper, including surface free energy, smoothness and gloss of some standard papers used in lithography on the ink transfer while matching the colorimetric values defined by ISO 12647-2:2013. Determination of amount of the ink transfer, optical density, mottling and colour difference of pri...

Adjustable color transformation model

Color management is an important part of the print production process. This paper presents a color transformation model which can provide all possible four-color solutions (CMYK) for a given aimed color (CIE L*a*b*). The model also allows quick adjustments of gamut mapping and total ink limit (TIL). The tests showed that the presented model is quite accurate. The model is less accurate for colors near the gamut boundary, but there is potential for improvements. Very high accuracy was achieved by avoiding gamut boundary colors. In practice, this is useful for application to image re-separation, usually with the aim of ink saving....

Analysis of the GCR Communication Channel For Image Steganography

Main motivation behind this investigation is to determine how and to what extend Gray Component Replacement (GCR) influences a color image. Specifically how GCR influences images in spatial domain, as well as in Fourier and Cosine domains. This is important to determine in order to develop a data hiding technique that can be used in GCR communication channel. To evaluate the influence of GCR on color images a large dataset is first converted from RGB to CMYK color space with very aggressive GCR. Then the original and the converted images are compared in Fourier and Cosine domains. The results show that the GCR communication channel has a nonlinear impact on the image that depends exclusively...

Sources of errors between color transforms

Characterization of output color reproduction devices has the purpose of ensuring accurate color reproduction. In the characterization process, two transforms are required: from device dependent colorant space to device independent color space, and in reverse direction. This paper identifies the sources of discrepancies between forward and reverse characterization models and investigates possibilities of their improvement. It is shown that lookup tables such as those used in ICC profiles inherently introduce errors near process boundaries. Partial improvements are possible by populating tables with proper values in critical regions....

LS fitting of the material properties influencing the print quality in flexographic reproduction system

Printing quality is influenced by numerous parameters and by the material interactions in the ink- plate-substrate system. The aim of this paper is to characterize and quantify influential parameters in the flexographic reproduction system by using the method of the least squares (LS fitting). Specifically, this paper deals with influential properties of the printing plates and porous printing substrates (paper, board). Printing plate with its properties and interaction with the printing ink and substrate during the printing process affects the parameters of the print. Different properties of analysed porous substrates define properties of the print such as tonal values/dot gain and optical ...

Analysis of the interactions In the “varnish – photopolymer” system

Varnishing of the printed product is often carried out by means of a photopolymer flexographic printing plate. Various types of varnishes interacting with a photopolymer material can cause chemical changes in its surface layer and affect the acceptance and transfer of varnish to the print. The aim of this paper is to describe the interactions of different types of varnishes and standard styrene-isoprene-styrene flexographic printing plate and to analyse the influence of varnishes on the surface layer of the photopolymer material. Types of varnishes used in this research are matt and gloss water-dispersive varnish, oil-based and UV varnish. Their interactions with the printing plate were anal...

Influence of the ink and substrate properties on the ink transfer in lithography

There are many parameters influencing transfer of the printing ink onto the printing substrates. Beside printing press characteristic one of most influential parameters is interface interactions in the offset blanket-printing ink-printing substrate system. The aim of this paper is to determine printing ink and substrate properties as an influential parameter to the printing ink transfer, […]...

Applicability of TensorFlow environment in colorimetric analysis

TensorFlow environment gained a lot of momentum in recent years due to the increasing need for a fast, flexible and open source solution for a high performance numerical computation. Developed by Google Brain team, TensorFlow supports machine and deep learning across different industries. In this paper, TensorFlow is tested using colorimetric data and compared with […]...
Item Specification
GCR - Python GitHub repository
Image Attacks GitHub repository
GCR Model Code, test images and results
GCR / DFT Model CodeOcean repository
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    M.E.G.A Project

    University of Zagreb, Facluty of Graphic Arts
    +385 1 2371 080