As a natural polymer, skin and its products, such as leather, have long been a
human interest. The handwritten book and its manuscripts made of parchment and
different leather products are among the most valuable heritages of humanity and
human civilization. Many of these artworks are at risk of erosion and extinction due to
natural damaging environmental factors or improper protection and maintenance.
Natural or artificial factors may influence the color change in these works.
Photochemical reactions in the degradation of these effects are intensified by natural
factors such as humidity, temperature, or light. They can break the chain of collagen
molecules in the skin and leather and disrupt these objects' cohesive structures. These
reactions damage the molecular chains of collagen and consequently alter its physical
and mechanical properties. In this regard, evaluating the appearance of leather in
defensive operations or selecting appropriate coatings may measure the proper
performance of protective polymer materials. Therefore, color change operations must
be considered for any conservation treatment. The options available for preserving and
finishing leather and skin artwork techniques are currently limited, and all have
drawbacks. In this study, the structure of the skin and its various erosion processes are
first discussed. The effect of aging on the discoloration of some conventional protective
coatings is then investigated. This article also emphasizes nanotechnology-based
solutions to maintain and preserve artistic and cultural artifacts to their original
features.
Keywords: Aging, Color, Leather, Parchment, Protective materials.