Areas with skeletal evidence marks alters the appearance of the parchment.
The skin is not homogenous throughout the body of the animal. The fibrous structure as well as the orientation of the fibres differs locally in surface area. The areas with skeletal evidence marks differ significantly in texture and characteristics from the other areas. Therefore, the transparency is these areas is different and the areas become clearly visible when light shone through it. Documenting the areas with skeletal evidence marks helps to determine which area of the animal skin has been used for the parchment document.
Due to the increased density of the skin and coat, these areas more difficult to process and finish. This can cause the unevenness of these areas and the subsequent degradation of the parchment.