C 6.18. Micro-biological damage, mould, grazing

Micro-biological damage is a general term used to describe the effects of bacteria, mould and pests (e.g. rodents, insects)

Mould is biological damage in the form of pigmentation splotches and softened areas.

Damage to a surface mechanically damaged by pests is defined as grazing. Biological damage can easily be identified visually, as it significantly changes the relief and appearance of the parchment surface. The damage is distinguished by grey, reddish-pink and other colour splotches on the surface. Damage makes the parchment fragile, thins the material and causes significant damage to the ink lettering.