The effects of artificial aging on the optical stability of a graphic product with non-wood fibers produced using three printing techniques

The aging process can lead to a deterioration of the basic characteristics of the graphic product, both functionality
and quality of image and text reproduction, resulting in an unsuitable final graphic product. Since it is an
irreversible change that takes place slowly over a certain period of time, the aging process cannot be eliminated.
Graphic products are usually based on fibers, which were traditionally derived from wood and still are the most
commonly used in the production of various paper substrates. The strength of cellulose fibers, and thus of the
graphic product, is primarily caused by the high molecular weight, highly oriented cellulose polymer in the
fiber. The cellulose polymer is formed from glucose units that are uniquely linked together to create cellulose
with better resistance to degradation. Although paper is a relatively stable material, it is subject to natural aging
processes, hydrolysis and oxidation resulting in degradation of cellulose. The recent significant increase in the
consumption of wood resources to avoid synthetic polymeric printing substrates has led to a worldwide demand
for alternative, non-wood cellulose fibers for papermaking. Therefore, the aim of this research was to analyze
the optical stability of a graphic product produced using three printing techniques (offset, gravure and screen
printing) on paper substrates containing 30% of alternative non-wood fibers from wheat, barley and triticale
straw. The effects of radiant energy, temperature, and relative humidity on prints produced with process ink used
in text and image reproduction on a graphic product were analyzed. The optical stability of the monocolor prints
was observed based on the difference in reflectance in the visible part of the spectrum and the color difference
compared to the optical stability of the monocolor print on 100% recycled paper.