No abstract

Introduction: Printing inks oil selection is related to the desired nature of the varnish in the ink production. Petroleumderived mineral oils and vegetable oils can be used in offset inks. Methods: In this study, the behaviors of vegetable-and mineral oil-based inks on uncoated and coated paper surfaces were investigated in terms of printability. Solid tone test prints were done with offset printing of these inks. Print gloss of the printed samples was measured and a light fastness test was implemented on these samples in order to determine the resistance to fading. Absorption behavior and contact angles of the ink-printed films on the test papers were measured with the sessile water drop method depending on time, and surface energies were calculated. Results: On both paper types, linseed-soybean oil-based vegetable ink gave the highest brightness value. The lowest print gloss results on the paper were obtained from soybean oil-based inks. The lowest color change was recorded with mineral oil-based inks on gloss-coated papers. According to the ink-film-surface relation, when the contact angle is high, surface energy decreases and the absorbency of the ink-film is lower. Conclusions: In this study, the behaviors of vegetable-and mineral oil-based inks on different paper surfaces, and the effect on the quality of printability as well as differences, have been evaluated, taking environmental and health factors into consideration.

Light fastness, in its broadest sense, is the resistance of colours to fading under the influence of a light source. Light fastness is one of the most important physical, and therefore visual, properties sought in both pigments and in the inks. Artificial and natural light causes most pigments to fade resulting in colour change. The light fastness of inks is important especially in the packaging and advertising industries. The posters and advertisements hung on the billboards used especially in outdoor advertising, printed product packaging and other printed products exposed to sunlight require high degree of light fastness. In this study, light fastness and factors affecting the resistance of the colour to the light were investigated and suggestions were made regarding high light fastness in terms of printability.

Offset is defined as a printing technique using a system of two-fluids (ink + dampening solution) that requires a constant monitoring and a balancing system due to the physical-chemical features of the process. Ink and dampening solution on the printing plate surface should not be intergraded during the chemical interaction. Image and non-image areas on the plate surface can be separated from each other only through the interaction of dampening solution and ink. The dampening solution is responsible for the wetting of non-image areas on a printing plate, and are applied to the entire plate. In the wetting process, the amount of the dampening solution on the plate should be at the lowest level. This can be provided only by lowering the surface tension of the dampening solution. Thus, quality printing results, such as edge sharpness, high color intensity and high print gloss are achieved with a small amount of wetting on the printing plate surface. In this study, the wetting of the printing plate surface is investigated under the effects of surface tension of dampening solution and its angle of contact with the printing plate and current studies related to the subject are reviewed and discussed.

Paper -ink interaction is extremely important in printing. Ideal printing outputs should be achieved with minimal ink consumption. It should not be supposed that visual printing quality will increase as the amount of ink increases. The effects of excessive ink consumption during the printing process on process sustainability, economy and environment should not be ignored. In this study, the effects of ink consumption during the printing process on printing quality parameters were mainly examined. Paper samples were printed with different amounts of ink, and the density and CIE L*a*b* values of the solid ink films were measured. The lightfastness test was applied to determine the resistance of the printed ink films to light, and the changes in their color were examined. Ideal ink amounts to reach ideal color L*a*b* values were determined and the effects of ink amount on the printing quality parameters were highlighted. Then, ink consumption was evaluated in terms of recycling, sustainability, environmental and economic effects, and recommendations were made to reduce the use of ink.