Metallized label paper requires special handling for printing. Most of the problems can be easily avoided if you follow the general guidelines for printing on non-absorbent materials.
In the first place it is recommended to print on metallic paper with folic paints, which are firmly secured as a result of oxidative polymerization. However, when working with these paints, it is better to abandon the anti- drying agents, since there may be problems with the paint dry on the print. In the case of high viscosity of paint, you can use print oil as an aid. Black paint is desirable to be printed the last, as it dries longer than other process paints.
It is important that fresh paint is constantly fed in the process of its consumption. Otherwise, the paint located on the ramparts, absorbs an increasing amount of moisture, which results in ink emulsifying and its flow stopping; hence – worsening of the ink embedding and drying on the print. With a large number of white space elements special paint driers shall be added to the paint; they release oxygen from the moisturizing solution and help to speed up the paint drying.
Printing of smaller images on large format machines is undesirable, as in this case there can be problems with image fixing. With a small print image having only one bold type line it is recommended to print a wide line behind the cut edge line. This improves the removal of excessive amounts of paint.
In order to achieve the necessary balance between the ink and the moisturizing solution is desirable to use replicable material. Due to the high cost of metallized papers and trying to save money, some printing houses are using for this purpose a conventional absorbing coated paper. In this case, however, after a few prints there occurs an excess of moisturizing solution. Otherwise, at printing the production run, the excess of moisturizing solution will lead to circles and cause a faded print. Besides, such drying of prints takes longer. After fixing the paint needs to be changed for a fresh one.
