HSLL researchers collaborated with Shaanxi Normal University, Xi’an, and the Sichuan Museum, Chengdu, China, as well as with UCL Institute for Sustainable Heritage, UK, in what is a pioneering piece of research into the material properties of 19th–20th century Tibetan paper.
Most of the available research into Tibetan paper focuses on the earliest books from an archaeological perspective. To explore the material properties and durability of the 19th–20th century Tibetan paper, scientific research was applied to reference historic materials. Material properties such as fibre morphology, paper pH, degree of polymerisation (DP), water and ash contents were investigated. The measurement methods for starch and protein content were explored – and we report on a quantification method for the determination of starch content in paper. The degradation behaviour of Tibetan paper was studied using accelerated degradation experiments at two sets of conditions (80 ˚C, 65% RH and 60 ˚C, 80% RH) for up to 84 days in order to explore the applicability of existing dose-response functions.
The results demonstrate that 19th–20th century Tibetan paper was prepared using diverse fibres, similar to traditional Chinese paper. Most of the examined paper sheets presented laminated structures, where starch was used as the glue. The layers within one paper were identical, as evidenced by similar pH and DP values of the layers in one sheet. Tibetan paper tends to have similar properties to mainland Chinese paper since they present pH 6.5–8 and DP 1000–2000. Accelerated degradation experiments show that Tibetan paper follows the same principle of degradation as western paper. This demonstrated that the rate constants of degradation depend on paper pH, temperature, and relative humidity of the environment. This research expands our understanding of Tibetan paper collections and informs preventive conservation of modern Tibetan manuscripts.
Download the paper published in the journal Cellulose here.
This research (COBISS.SI-ID 173593603) was funded through Slovenian Research and Innovation Agency projects Lignin (J4-3085), Ancient Book Crafts (N1-0271) and infrastructure programme E-RIHS (I0-E012).