It is a cardboard manufactured with pure ECF cellulose, compliant with the ISO 9706 Long Life standard, free from acids (Acid Free), which ensures its inalterability over time. The particular grain that distinguishes its surface and the extraordinary resistance of the colors to sunlight, are the main characteristics of Murillo and make the use of this Acid-Free cardboard advisable for fine editions, art prints, inserts, leaflets, calendars , passe-partout, drawing etc.