Identification of fibres and sizing of Timbuktu manuscripts using polarised light microscopy and Fourier Transform Infrared Spectroscopy

Abstract

The aim of this work was to determine the material composition as well as the optical characteristics of the fibres of the Timbuktu manuscripts. Analysis of the fibres was done using Polarized Light Microscopy (PLM) and sizing determination was done using Fourier Transform InfraRed (FTIR) spectroscopy. PLM was done with ordinary light, plane polarised light and cross-polarised light as well. FTIR measurements were done in reflection mode by use of Attenuated Total Reflection (ATR). The sample fibres were observed to be colorless with joints, surface irregularities fractures and swollen tissues. The retardation color was found to be yellow, with a birefringence of 0.060. These optical properties are consistent with hemp fibres. The total crystallinity index of 0.2 and lateral order index of 0.35 were deduced for the sample fibre. FTIR results showed that the sizing on the manuscripts were kaolin, gelatin and clay. These results provide useful insight in planning for the conservation of the Timbuktu manuscripts.