The third point is the glass: it itself protects the art from direct damage from the outside. However, the type of glass should guarantee additional protection. In contrast to window glass, UV glass protects against harmful UV radiation, which can attack, damage and thus change the paper and inks in the long term. The level of UV protection determines the permeability of the glass
for UV rays. The higher the value, the less harmful rays penetrate the art. This increases the guarantee of long-term color fastness. In addition, the glass should not be reflective to prevent reflections.