AKADEMIJI TEHNIČKIH ZNANOSTI HRVATSKE
INVESTIGATION OF GRAPHIC MATERIALS
Prof. dr. sc. Vesna Kropar-Vančina, dipl. ing

Grafički fakultet Sveučilišta u Zagrebu
10000 Zagreb
Getaldićeva 2

According to intense development of graphic technology properties of printing inks are changed, new materials are used and conventional and digital printing are integrated.The aim is to update and improve existing standards in order to have prints of good quality according to printing process, printing press, speed of printing, printing plate, printing ink, subtract and other conditions.
In Croatia there is no project that schematically investigates this subjects so interesting for digital and hybrid printing. For printing inks new characterizations and classifications are proposed based upon experimental printing.
Prints of various printing inks and subtracts should be investigated, as well as, the interaction of materials during formulation and production of inks and after printing. New methods of laboratory analysis of raw materials in printing inks, printing inks, laboratory prints and dry prints should be established too.
It is necessary to simulate in laboratory processes that take place in large pressrooms and obtain results use to define optimal solutions in real printing processes.
Comparison of laboratory models and real systems can be used to define new goals of investigation.
Parameters of the model used to investigate rheological properties of inks viscosity, flow and yield value, are the most important investigations of printing inks that are carried out in small series and than extrapolated to the real printing process.
Investigation of laboratory prints serves as a base for experimental design which is used to find out optimal combinations of printing inks and substrates. Experiments shoul be carried out with control and experimental group, because numerous parameters of integral printing processes dealing with interaction of materials i.e. inks, papers, polymers are still unknown. The main reason is appearance of new materials every day, new inks, papers, coatings etc, and consequences are great damages in printing processes.
Digital techniques use new materials too, and at the same time the usage of conventional materials is disrupted. Investigations should include models that simulate mechanical resistance, surface properties, chemical and optical stability of paper. Before the real printing process is investigated it is necessary to create models and simulate printing and use obtained results to understand "events" that take place in real systems and, also, to avoid expensive experiments in real printing.
Printability of paper is very important for printing. Printability of paper is the extent to which the properties of paper lend themselves to the true reproduction of copy by the printing process used. Printability of paper is determined by optical, chemical, surface and some mechanical properties.
Durability of paper is, also, important for printing. Durability is the ability of paper to maintain its properties with continued usage and handling.
Investigation of printability and durability of paper in the laboratory before real printing process is very important.
Investigation of interaction of printing inks, adhesives and coatings with various papers by measuring smoothness, contact angle and absorption of paper shoild be done too.
The permanence of paper has to be investigated, because the paper is still the most important carrier of our written and printed cultural heritage. The permanence of paper can be investigated by measuring its chemical and optical properties before and after accelerated artificial aging.
For deteriorated papers more effective methods for restauration and conservation re necessary. The influence of humidity in air, as well as, the contamination by air shoul be investigated in laboratory conditions. The influence of microorganisms and molds has to be investigated too.
Special part of investigation shoul be focused upon polymers and polymer materials that are frequently used in graphic technology. Films and foils made from various polymer materials do not, practically, differ in appearance but these materials have completely different properties and that is why printers have a lot of problems during printing, packing and lamination.