engleski

Optical and Colour Durability of Graphic Board and Laboratory Prints

Paper and board carriers of written cultural heritage remain important materials, so nowadays as in near and far future, because of their high permanence and durability. During the period of last ten years the book and document conversation, especially of those from the19th and 20th century that show the signs of very quick decay in archives, libraries, museums, galleries all over the world, represents very important activities that demand quick and effective steps. The difference in quality of individual type of paper and board lies in their overall composition with regard to raw material such as fibers, fillers, sizing agents, dyestuffs, pigments and technological conditions of manufactures and surface treatments. We have studied coated and uncoated boards, of various producers and the same nominal grammage about 250 g/m2. Accelerated aging of boards has been performed according to ISO 5630. The aim of the work was to determine the quality and durability of investigated boards. The durability of basic, surface and chemical properties, mechanical endurace, optical stability as well as printability of boards were investigated. It can be concluded that the retention of chemical, mechanical and optical properties depend mainly upon the board composition and type of coating. The law chemical and mechanical stability are proportional to the content of CTMP and recycled fibers. The change of surface properties (smoothness, contact angle, absorbency and water penetration) is strongly influenced by the type of coating and surface treatment of board (binders, pigments). After aging the surface roughness is increased while for absorbency increased and decreased values are obtained. Changes of optical properties of investigated boards are great - the brightness is decreased while yellowness increased according to the surface treatment of board and optical brightener content and coatings. The changes of lightfastness of laboratory prints is slightly pronounced because the lightfastness of used printing inks is much better than lightfastness of investigated boards.

durability optical and colour; graphic board coated and uncoated; laboratory print

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