Thermal analysis on parchments II: Micro-DSC approach to assess and rank heat damages at a molecular level

New and artificially aged calf parchments by heat stress were investigated through the application of micro-DSC on samples of finely minced parchment suspensions in buffered environments. Criteria were assessed to define a unique normalized damage index (D.I.) parameter that aims at ranking, in a range from 0 to 1, the heat damage experienced by parchment collagen at a molecular level, and that is suitable for a direct application to historical parchments. The results indicate that such a calorimetric methodology is more sensitive in revealing damages deriving from mild heat stress than the analogous damage index previously proposed by the use of a DSC-TGA approach on parchments as-is. Synthetizing the overall injury extent in a unique numerical parameter represents a useful tool for ranking parchment conditions through simple calorimetric methods to help screening procedures and preservation strategies of such cultural heritage handcrafts.