"PERMANENT" paper means paper that, under normal conditions of use and packaging, does not change significantly in terms of its visual appearance and internal resistance for at least 100 years.
 In a more technical and precise way, to be classified as "PERMANENT PAPER" the product must meet the international norms of procedures of methods of analysis as well as the minimum specifications. The internationally accepted European standard, ISO 9706 requires:
 pH between 7.5 and 10
 Oxidation resistance with kappa number less than 5;
 Alkaline reserve 20 grams of calcium carbonate per kg of paper;
 Tear resistance: minimum of 350 Mn for papers over 70grs.