A letter from the Editor
Three papers in this issue were accepted for publication during the very last days of December 2017. The first one is a study and theoretical explanation of the unwanted effect of bulging-out shoulders in screen printing, often used printing technique in research and production of printed electronics and in industrial printing, where the dimensions and predictable thickness of the layer of functional ink is a necessary condition for a success of printing.
The second paper is an overview of the developments and use of alternative halftoning techniques adopted for improved sharpness and definition of a monochrome or colour printed reproduction of the originals with sharp edges and fine details. This review paper is mainly based on author’s own research, publications and patents in the last decades, with a comparison and description of his findings as an alternative to established halftoning techniques from other authors and industrial vendors.
The research of possibilities for the use of RFID tags on relatively inexpensive dairy products is discussed in the third paper. Price and cost limitations on the consumer side were confirmed and consequently, the predictions regarding the wide use of RFID tags and other printed functionality on consumer packaging should be reconsidered in the future.
In the current Topicalities section, prepared by Associate Editor Markéta Držková (email@example.com), an overview of the publications from CIE, Ghent Workgroup, and Fogra is introduced. The interesting topics from these reports are dealing with multispectral imaging, testing of LED lights, advances in PDF 2.0 workflow in print production and research report on abrasion test results. The short reviews of the newly published books cover 3D/4D printing, Internet of Things issues, advanced use of inkjet for printing with chemically reactive inks, and books on new materials for functional printing, on design and on a role of colour in modern life. Also, the new book on halftoning strategies is bringing additional information on the topic, presented in the scientific section.
Three interesting theses are introduced in the Topicalities Bookshelf. The thesis on a design of a newspaper defended at the University of Reading by Jasso J.J. Lamberg is bringing an overview of the concepts, processes, trends and the role of the designer in newspaper design and production. Carina Bronnbauer defended her thesis on printed dielectric mirrors at the University Erlangen-Nürnberg. The aim of her work was to develop an alternative production pro.cess for dielectric mirror stack usually prepared using vapour deposition processing and eventually employ it as a part of printed organic electronics devices. The third presented thesis was defended by Diogo José Horst at the Federal University of Technology Paraná, Brasil. The aim of this thesis was a study of the properties and usability of vegetable resins in additive manufacturing, which was recognized as a challenge due to the use of natural bio-material, exposed to bacteria and pathogenic microorganisms, in 3D fused deposition modelling process.
A number of global events are presented in the final chapter of Topicalities, dedicated to different topics from com.puter vision, imaging, colour science and colour management to printed electronics, 3D printing, new materials, and publishing.
This short overview of the activities in our research field(s) is promising and encouraging. We are not limited only to traditional print and media technology research. Printing processes are nowadays used in many emerging technologies, not only in printed electronics and additive manufacturing. The use of printing technology in different ways and for different purposes, other than for printing books, periodicals or packaging, is calling for new design approach and for the use of new materials, methods, production technologies, as well as the use of final products and services. Thus, the scientific and research field of print and media technology is really wide, interdisciplinary and oriented to the future.
On the other side, the demand for qualified publishing channels in the scientific community, recognized in Web of Science, Scopus, and some other worldwide known indexing and abstracting systems, is constantly growing. The advantage of the Journal, indexed in ESCI and accepted by Scopus in comparison to any local Journal is evident. The call for quality papers for publication in the Journal is constantly open and we can expect publication of interesting research results in the future issues of the Journal of Print and Media Technology Research.
Ljubljana, December 2017
JPMTR 101 | 1711 Original scientific paper
Considerations on bulged-out print shoulders due to mesh depression and high ’emulsion over mesh’ in screen printing
Institut für Innovative Anwendungen der Drucktechnologien (IAD), Hochschule der Medien, Nobelstr. 10, 70569 Stuttgart, Germany
In screen printing sometimes at the edges of an ink deposit that is wider than a few millimetres a phenomenon occurs, which can be described as an elevated edge or better as bulging-out shoulders. This can be a print quality issue if subsequent overprints need to be carried out. The shoulder bulge-out effect typically occurs if the stencil build-up is not well adapted to the targeted type of print pattern (e.g. fine lines vs. large solid tone areas). The effect is described in screen printing textbooks and some scientific articles but not yet tackled theoretically. As an approach, here a simple model, assuming a quasi-infinite line as the pattern to be printed is used. The model combines the elongation of the mesh caused by the mesh tension and the additional stress applied by the squeegee with material properties and calculates the depression of the mesh towards the substrate during the squeegee movement between the two edges of the stencil opening. The developed relationship ends up in an equation that is solved numerically by means of a look-up-table (LUT) approach. Graphs are derived that show the dependencies on print line width, stencil build-up, stresses applied and materials used.
Keywords: print quality, squeegee pressure, mesh elongation, ink deposition
JPMTR 102 | 1713 Review paper
Optimal image encoding for hard copy production and method of its efficiency estimation
Yuri V. Kuznetsov1 and Andrey A. Schadenko2
E.mails: firstname.lastname@example.org; email@example.com
1St. Petersburg State Institute of Cinema and Television, Ul. Pravdy 13, St. Petersburg, 191119, Russian Federation
2St. Petersburg State University of Industrial Technology and Design, Ul. Jumbula 13, St. Petersburg, 191180, Russian Federation
Unlike in a soft copy generating, the multilevel pictorial data are, after capturing by camera or scanner, once again encoded in prepress to get the output signal governing the halftone printing in bi-level, “ink – no ink” fashion. Criteria of such encoding optimization are comprised in the transfer through physical plate making and press communication channel onto a print with as much as possible of original image data perceivable for a viewer. It undermines the pro.viding of mutual conformity for parameters of a source image and channel, as well as for properties of an output print and vision. On the background of the screening developments overview for the last half a century, the paper presents: discussion of tone spatial dispersion in halftoning and accompanying contour and fine detail distortion; such distortion corrections and the method of quantitative estimation of their efficiency; principles of an image optimal encoding in prepress and their implementation in the High Definition Halftone Printing (HDHP); including results of testing and promotion issues of its practical application; and disclosed approach potential with the spatial dispersion adaptive to an arbitrary contour. Samples of test images and fragmentary photographs from illustrative print trails and jobs using HDHP are also presented. On this basis, the paper pretends to disclose some mainstream aspects bypassed in the most of other publications on halftoning.
Keywords: image data encoding, halftone dot, printing, adaptive halftoning, image sharpness, print definition
JPMTR 103 | 1712 Case study
The possibilities of RFID and NFC tag implementation in dairy segment
University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Textiles, Graphic Arts and Design, Snežniška 5, SI-1000 Ljubljana, Slovenia
With the help of printed electronics, the product-consumer relationship can be further evolved and explored, thus enabling the building of a deeper emotional connection. The growing implementation of online connectivity – Internet of things, is one of the important driving factors for the printed electronics market. The goal of our study was to estimate implementation options of printed electronics into the packaging of dairy products according to the type of packaging with considering the approximation of the cost per unit. Knowing that the dairy segment is mainly a commodity, we assume this implementation will have a big influence on the product price. Our research showed that the added value in the commodity segment is too low to be able to cover the cost of implementation of the RFID tag. Printed electronics and, generally speaking, smart packaging has found its place in a segment where a need for security elements or the product is higher priced and the extra cost of a tag does not represent a high burden. There is a great potential in the packaging of pharmaceutical and cosmetic products, where the product’s identity is key. There is also a potential in a food segment where food safety is crucial; these are nutritional products for children, for example, baby milk. The main obstacles of printed electronics and smart labels, in general, are in the high unit price per product because the uses are mostly carried out on luxury goods and those are smaller in quantities. Taking it into consideration the printed electronics providers cannot achieve large quantity productions and therefore lowering of price because the economy of scale is insufficient. Until there are no implantations in the segments where the quantities are high, the RFID tag has lesser chance to get its price lowered.
Keywords: smart packaging, consumer interaction, aseptic packaging, food packaging