The Influence of UV Varnish on Colorimetric Properties of Spot Colors

Galić, Eduard; Ljevak, Ivana; Zjakić, Igor

doi:10.1016/j.proeng.2015.01.525

Cited by 11 publications

(12 citation statements)

References 13 publications

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“…There are various varnishes on the market and the composition of varnishes is complex, but they can be classified according to the application technique (lithography, flexography, screen printing, or digital printing), by the visual appearance of the finish (matte and glossy effect) and by composition/drying method (water based or dispersion, conventional offset varnish, oil based, and UV varnish) 8 . Although varnishes are printed over the image and should be colorless, varnishing has the tendency to create color shift of the printed image 15‐18 …”

Section: Introductionmentioning

confidence: 99%

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

Cigula

Hudika

Donevski

2021

Color Research & Application

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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 prepared samples were evaluated by measuring surface coverage, tone value increase (dot gain) of primary colors and calculating ΔE00 of defined tertiary colors. The results showed that gray component replacement application reduces ink consumption. Higher gray component replacement applied results in lower ink surface coverage, but the decrease is also dependent on the image content. The TVI (dot gain) is significantly influenced only by applying UV varnish, resulting with higher TVI. The color differences of the tertiary colors showed that increased level of the gray component replacement applied did not cause significant color differences, even decreased color difference in some cases. Additionally, applying gray component replacement decreased color differences in “reddish” part of the gamut. This research proved that lowering the ink consumption due to the gray component replacement will not cause significant differences in the color reproduction. Furthermore, varnishing with commercial offset or water‐based varnish will not cause higher deviations in color reproduction, but use of the UV varnish would.

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Section: Introductionmentioning

confidence: 99%

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

Cigula

Hudika

Donevski

2021

Color Research & Application

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“…The coating materials are usually acrylic or photo-curable varnish [8,9], PET, PE or PP laminates [10]. On an optical point of view, the coating material has not much importance, except its refractive index, absorption coefficient and surface topology which can however have a strong impact on the print appearance, especially on the color gamut [11][12][13] and the glossiness [14][15][16][17]. These changes of appearance can first be explained by a change of surface topology of the material, since adding a coating layer can smoothen the surface of the material and reduce light scattering on it [18,19], or, on the contrary, increase the surface scattering [20].…”

Section: Introductionmentioning

confidence: 99%

“…If the effect due to scattering within diffusing printing supports has generated a profuse literature [30][31][32][33][34][35][36][37][38], it seems that the halo effect due to a transparent coating has never been evocated as such in literature, neither theoretically or experimentally. Of course, the two optical dot gain effects can add mutually, and this is a possible reason why the halo effect has not been clearly identified (it has been noticed in [12,13] that a glossy coating introduces additional dot gain but no physical explanation is provided). There is therefore no available information indicating to what extent the phenomenon, independently of other phenomena, contributes to the global dot gain effect, and to which extent and in which conditions the coating, even perfectly clear, can modify the halftone colors.…”

Section: Introductionmentioning

confidence: 99%

Impact of a Transparent Coating on the Reflectance of a Line Halftone Pattern

et al. 2021

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Many prints are coated to increase their resistance or to enhance their appearance. Applying a smooth transparent layer on a print darkens and saturates its color, an easily observable effect which can be predicted in order to obtain better color management of coated surfaces and ink saving. A model was thus developed which describes the reflectance of a single-ink line halftone in optical contact with a transparent smooth coating. It is based on the peculiar way light diffuses inside the coating layer, a phenomenon called the “halo effect”. The model was compared to two experiments conducted at different scales where line halftones were coated with different coating thicknesses. The experiments enabled us to identify and measure the darkening effect caused by a coating layer, and validated the model.

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“…The purpose of this analysis is estimation -which indirect methods might be used in order to evaluate whether the printing is enriched with transparent varnish layer or not. In the case of color layers of printing inks, the quality of the layer might be checked with reflectance densitometry or spectrophotometric techniques (Galić et al, 2015). However, this method are useless in the case of transparent layers.…”

Section: Introductionmentioning

confidence: 99%

Measurements of surface free energy as a tool to asses the effect of varnishing and printing of the paper substrates

Żołek‐Tryznowska¹,

Więcek²

2020

Proceedings - The Tenth International Symposium GRID 2020

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Nowadays, printing products might be finished in various ways. Varnishing process is one of the most popular finishing method which gives various effect, such as mate, glossy etc. However, the varnish layer applied on the paper is very thin, therefore it can be invisible to the naked human eye. The aim of this work was to use contact angle measurement and surface free energy determination as a tool to assess the effect of printing and varnishing process of paper materials. We have used various tools in order to analyses the changes of surface: surface roughness, gloss, water contact angle absorption and surface free energy determination. Those tools were used in order to confirm whether the print has been covered with varnish or not. In this work six various paper substrates were used (glossy, coated and un-coated papers). The printing and varnishing was performed in laboratory conditions using flexographic water-based printing and waterbased varnish. Samples were prepared as follows: paper with ink coating, paper with varnish coating and paper with ink layer and varnish layer on the top. The surface roughness was determinated of all samples and compared. The surface roughness changes were observed for pure paper, overprinted and overvarnished. Next, the gloss of samples prior and after printing and varnishing was measured. The gloss of the samples increases when they are printed or varnished, what is related with properties of ink and varnish. Also, the thickness of ink and varnish layers was determinated. The thickness of the samples increases when the number of layers increases. Finally, the water contact angle was measured and surface free energy was calculated with Owens-Wendt method. Our results reveal the possibility of using various tools in order to confirm the performance of varnishing of the prints. The printing with various colors is always seen by the naked human eye. On the other hand, the varnish layer might be not visible. However, such a comparison is not possible if we do not have the pure paper substrates prior printing or varnish.

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The Influence of UV Varnish on Colorimetric Properties of Spot Colors

Cited by 11 publications

References 13 publications

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

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

Impact of a Transparent Coating on the Reflectance of a Line Halftone Pattern

Measurements of surface free energy as a tool to asses the effect of varnishing and printing of the paper substrates

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