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In order to achieve high-quality colour prints by using an electrophotography (EP) printing machine, it is necessary to prepare the printing substrate. Additional treatment may be needed to achieve better substrate surface tension for optimally attaching the liquid EP ink to the paper. To ensure good adhesion of the ink to the printing substrate, a corona treatment may be used. During the corona treatment, the surface of the paper is modified, and the ability of paper to accept the ink is improved. In this study, we will determine the possibility of realizing CMY prints and of achieving an increased range of tone value in EP digital printing. Based on the results, the new possible values of reproduced CMY tones will be determined, so that higher print quality can be achieved. The results show that the best colour reproduction is achieved without the use of corona power (0 W). The additional activation of 450 W corona will result in the greatest colour variation of ∆EC = 0.60, ∆EM = 0.60 and ∆EY = 0.48.

Varnishing is often used to protect or decorate the print, but it can also influence the print’s colour appearance. Therefore, varnishing should enhance the print role, while colour change should be kept as low as possible. The aim of this paper is to evaluate inkjet UV LED varnishing by estimating optical print characteristics. Prepared offset prints were UV LED varnished in different surface coverage values (SCV) with a matte and gloss finish. The prints were evaluated by measuring gloss and colour coordinates. Secondly, varnishing was performed in a different SCV, which enabled assessing the optimal SCV, i.e. the most cost-efficient varnishing. The printing process was conducted in a standardized and controlled laboratory environment, regulated via the ISO 12647-2:2013 norm to ensure that the black colour was reproduced in the standard tolerance. The results showed that the colour difference is negligible (stays in the ISO tolerances), regardless of the varnishing SCV. On the other hand, the optimal printing gloss is at the SCV of 100%.

For high-quality black & white printing realized with an electrophotography printing machine, it is necessary to prepare the printing substrate. For optimal adhesion of the black liquid electrophotography ink to the printing substrate, it is necessary to apply additional treatment to meet ideal substrate surface tension by means of corona treatment and/or coating with fluid for regulating the surface tension (primer). This paper examines the influence of the corona power and the thickness of used fluid for the regulation of surface tension on the achromatic digital reproduction quality. Within the electrophotography printing process, this implies determining the differences in the colour gamut volume, the structure of characteristic screening elements, the amplitude-modulated screening, and the increase in the number of colour separations. The results show that the optimal colour tone values, colour gamut, and dot gain, high quality of digital prints will be realized without the use of the fluid for the regulation of surface tension and without activation of the corona power. That confirms that the FOGRA values for industrial standards can be used for quality electrophotography printing.

One of the problems in the offset printing technique is the picking of uncoated paper, which occurs due to the activity of pressure cylinder and sticky offset inks. To reduce offset ink stickiness, it is possible to add cheaper ink filler that will indirectly reduce the concentration of pigment. However, there is also a reduction in the colour tones and quality of reproduction. In this experiment we used: standard cyan offset ink (Sun Lit Express ink which consists of phthalocyanine based pigment) and high-quality gloss coated cardboard (250 g/m2 Euroart plus gloss). This paper aims to show how the CTP screening type (AM/FM mode) and the CTP line screening (80, 100, 120 line/cm and 10 μm, 20 μm 25 μm diameter of print elements) manifest on the reproduction quality of a standard gradation wedge. This research will create the possibility of correlating the factors of user reduction of pigment concentration and reproduction quality of cyan colour separation. By using the AM screenings and adding different concentrations of ink filler, more stable cyan prints are achieved.

An increasing requisite regarding the reproduction quality of electrophotographic printing machines demands improvement of new electrophotographic toner formulation, especially used pigments. The subject of this paper is a comparison of prints realised by depositing high chroma (HC) and standard emulsion aggregation (EA) toner on gloss fine art paper. HC toner has a different composition of the cyan and magenta tones compared with the corresponding standard EA toner tones and therefore behaves differently under real conditions. The patches used for this experiment were cyan and magenta tone prints with tone values (TVs) of 0, 20, 60 and 100%. Ultraviolet (UV) degradation was measured over time intervals of 0, 6, 12, 24, 48, 96, 144 and 240 h for all patches. Results (laboratory values) were calculated using colorimetric difference. Values were plotted as a function of time in tonal degradation graphs. A model was created using non‐ linear regression‐based modelling. The experiment demonstrates that magenta patches are more susceptible to degradation in comparison with cyan patches. With the increase in tonal value, it is noticeable that the colorimetric difference is higher. Colorimetric differences calculated using HC magenta toner and standard EA cyan toner (100% TV) were higher than ΔE = 5, starting to appear after 6 h of exposure to UV radiance. After 12 h of exposure, colorimetric differences of standard magenta tones that were greater than ΔE = 5 alsonstarted to appear. Cyan patches (100% TV) printed with HC toner were more stable than the other patches, and after 240 h of exposure had not crossed the boundary of ΔE = 5.

Everyone has the right to freely participate in the cultural life of the community (United Nations, 2012). In Europe and around the globe, many efforts have been made in order to include people with visual impairments and blindness into the cultural life (Braille Authority, 2012; Brvar, 2010; European Blind Union, 2011; Kennedy, 2003; Kurze, 1996; Salzhauer Axel & Sobol Levent, 2003; Wright, 2009). The objects and artifacts exhibited in museums for people with visual impairments are available either by direct touch of the original or its 3-D reproduction. Paintings, on the other hand, require a different approach--usually a tactile adaptation is created. This paper describes the process used to create a tactile adaptation of the painting Portrait of Empress Elisabeth of Habsburg, which hangs in the Celje Regional Museum in Slovenia as a part of the Cultural and Art Historical Collection. It was painted between 1873 and 1875 by the Austrian artist Georg Martin Ignaz Raab. The Empress Elisabeth, also known as Sissi (1837-1898), was famous especially in the Habsburg monarchy for her extreme beauty and unconventional style of life. Her life inspired many movies that ensured her legacy for generations to come. There are many techniques used in tactile adaptation. Two are used very often, namely the microcapsule technique (Braille Authority, 2012) and the thermovacuum technique (Rener, 1992). To create a tactile adaptation in this study, a new technique with an inkjet printer, the Roland UV LEC-330, was tested (Roland, 2012). The printer uses a special varnish that can be cured by ultraviolet (UV) light to generate raised relief surfaces printed layer by layer. This cannot be used for numerous copies, though, as the printing procedure is very time consuming. The printer adjustment and mistake correction are simple because the technique is digital. Apart from these technical aspects, we also explored ways of conveying the content of the actual image as best we could (Salzhauer Axel & Sobol Levent, 2003). The painting was carefully transformed into a tactile adaptation with the help of a museum expert; thus, during the adaptation, all historically important data were preserved. The process unfolded in three stages that are described below. In each stage, in addition to the technical use of the printer, subjects who are blind or visually impaired were interviewed to tell us whether the information at that point in the adaptation was easily perceived tactilely or not. Their comments were taken into consideration in the following stage. The final, third adaptation now hangs alongside the painting in the museum, where it is available for museumgoers who are blind or visually impaired. METHODS Subjects The subjects who participated in this study were found with the help of the Slovenian Association of People with Visual Impairments and Blindness and the Institute for Youth with Visual Impairments and Blindness of Slovenia. Our aim was to exhibit the tactile adaptation in a museum. Our main criterion was, therefore, that subjects be interested in art and the exploration of art. The average age was 35 years. All subjects agreed that tactile adaptation is useful and a likeable medium that helps improve their understanding of the visual world. Not all subjects were involved in all three stages of the adaptation. In Table 1, their involvement and some demographical data are presented. Three stages of adaptation The painting's dimensions are 79 x 63.3 centimeters (roughly 31 x 25 inches) (see Figure 1). The tactile adaptations, due to size restrictions connected to the sense of touch, were smaller--only 36 x 29 centimeters (approximately 14 x 11 inches) in size (Brvar, 2010). The three tactile adaptations were printed in a similar way, with only minor differences. Table 2 shows printer settings and printing conditions. The appropriate museum expert was consulted throughout the procedure; however, the historically relevant features were determined beforehand. …

The machine printing and rapid cultural development in Europe begins with the discovery of metal lettering at the end of the 15th century. This printing technique has been named the letterpress printing and is one of the greatest inventions of mankind. The development of printing was one of the main indicators of the development of individual countries. We believe that today in the world and in Europe the Croatian development of that age is significantly neglected. This paper presents European development and development in Croatia. This paper will contribute to a more accurate evaluation of Croatian printing and cultural level of that time by displaying Croatian achievements of that era, the printing staff, printed works and printing houses, throughout European and Croatian development of printing.

The aim of this work was to determine the dependence of the colour fading of offset prints on the ageing process, relative to prints overprinted with water-based dispersion varnish and UV-cured varnish. Natural ageing (outdoor conditions and the exposure to sunlight filtered by glass windows) and accelerated ageing (moisl heat and light xenon arc lamp) treatments were carried out. In order lo determine colour fading, colour difference, 2D gamut values and characteristic cross sections L20, L50 and L80, as well as 3D gamut values were used. The yellow colour showed the largest colour difference when offset prints were exposed to accelerated ageing by means of exposure to xenon light. Magenta followed yellow. No significant stability was achieved by varnishing the yellow print with water-based dispersion varnish and UV-cured varnish. This was also the case with magenta. An increase of the gamut occurred after one week's exposure of prints coated with water-based dispersion varnish to moist heat ageing. In contrast, on exposure of prints coated with UV-cured varnish, a decrease of gamut appeared. On further exposure of prints covered with either kind of varnish a decrease of gamut was evident. Indoor exposure of varnished prints to sunlight through a glass window had a minor influence on the gamut volume change in comparison with the exposure of prints to outdoor conditions.

Printed fabric is widely used, and it is exposed to various influences. One unavoidable impact is heat treatment during subsequent maintenance – ironing. Hence, many printed textile materials are exposed to different temperatures. Textile can be printed with conventional (screen) and digital (Inkjet) print technologies. In this paper, we analyzed screen printed textile and its sustainability after heat treatment. Heat can not only change the reproduced colour, but also affects the print uniformity (print mottle). The goal of this paper was to find what could be controlled and changed in order to get long-lasting printed textile. We used one natural textile material – cotton that was printed with screen print technology. Constant parameter during the experiment was a time of heat treatment. Ironing temperature and screen mesh count were varied. Results showed that samples printed with smaller screen mesh count maintain print uniformity after heat treatment.

This article aims to define attributes of image quality that affect the quality of textured UV varnish applied as a pattern effect over offset prints. The most common UV varnishing problems that might influence attributes of print quality are reticulation of the varnish, poor adhesion, spreading of the varnish and shade changes. These problems mostly arise from inability to control the coating, especially if applied on differently generated print surfaces. Benefits of UV coatings in terms of image quality improvements might be greater opacity, color stability, deeper and more vibrant colors, sharper graphics, higher gloss and uniform surface to give labels a more vibrant look. Image quality variation assessment often needs to be carried out since an improvement made to one attribute can result in a deficiency to another attribute or attributes. In order to determine correlations between these attributes, a combination of objective and subjective image quality assessments has been applied.

In accordance with environmental sustainability and in order to optimize the recycling process of prints from indirect electrophotography with liquid toner the results of investigating the effects of changes in printing conditions on the characteristics of recycled fibres is presented. Changing of printing machine conditions, respecting of voltage variations, comprises of the reverse rollers and intermediate cylinder. Based on the results it can be concluded that the change in the voltage of the reverse rollers more affect the recycling efficiency with respect to the voltage change of the intermediate cylinder. Brightness gain is higher when the print for recycling is made on uncoated paper compared to coated, and dependent on the voltage changes. Effective residual ink concentration decreases far more on handsheets obtained from recycled samples on uncoated paper in relation to both sides coated paper. Increasing the positive voltage of intermediate cylinder and increasing the negative charge of reverse rollers increases the 3 D gamut CIE L*a*b* color cubic units. Guidelines for the size of the voltage in order to obtain optimal print reproduction are provided. The further research will include the development in area of clean technologies, advanced materials, closed loop systems; therefore the significant terms in the area of environmental sustainability.

In this paper, the influence of resolution on the color quality reproduction in digital offset printing were investigated. In our experiment special test charts were printed with different resolutions and compared. The results show that high resolution improve image contrast but not the color reproduction.