Dating Feasibility of Unknown Historic Scripts through Thermal, Spectroscopic and Microscopic Identification of Paper Materials

Historic papers contain valuable information about national, cultural, artistic and historical identity and values of every civilization. Identification of paper materials such as fiber type, sizing, and other materials can significantly help to obtain valuable information concerning old civilizations, their attitude, culture, geographical origin, and etc. However, there are some manuscripts that their writing date remains still unknown. Qualitative and quantitative analytical methods can be used as a tool to identify paper materials and therefore dating of historic papers as a cultural piece. In this research work, the dating feasibility of four unknown historic paper scripts was investigated through analysis and comparison of their materials like characteristic and type of fiber and sizing material with four known samples belonging to Safavid period. For this purpose, different techniques such as optical microscopy, color indictor assay, Fourier Transform Infrared spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) were used to characterize paper materials. Using each characterization method, some information about physical, chemical, apparent form, and genus of paper materials were obtained. The results of fiber identification tests including optical microscopy and color indicators assay revealed that, except one sample made of kenaf fiber, all samples were made of flax fibers and no wooden fiber was used in paper making. FTIR data confirmed the presence of cellulose and hemi-cellulose and lack of lignin within all paper samples. Moreover, sizing material used for paper making was polysaccharide type, i.e., starch. TGA and DSC analyses results showed that depending on its thermal and chemical history, each sample had peculiar thermal behavior. Furthermore, compared to cellulose, hemi-cellulose possessed lower thermal stability. Overall, the results of this study revealed that dating of unknown samples through combination of thermal analysis and other characterization methods is possible, so the unknown samples belong to Safavid period. It is to be mentioned that the main goal of this research was dating unknown samples made of papers materials, which in this case all of them were similar. Although some samples may belong to different period, other parameters such as type of contents, differences in aesthetics, type of script, and etc. may be used to distinguish the sampled belonging to the same period. The data obtained in this research can be used in preparation of database for possible identification and dating of unknown historic samples.