Analysis of Orientation of Fibers in Historical Papers Using Small Angle X-Ray Scattering (SAXS)

Determining origins of historical paper involves both material and technology identification. Sheet formation is a technological process that over time evolved into local varieties and its identification can aid in paper artifact profiling. Scanning small angle X-ray scattering (SAXS) complemented by microscopic and image processing techniques was used as a tool in determination of fiber orientation in paper sheets formed by one of three principal, historical methods; one-time dipping (European papers), scooping also called nagashi-zuki (East-Asian papers) and pouring (Highland and Southeast Asia).

Results of fiber orientation analysis for a set of mock-up samples reveal trends characteristic for groups representing individual sheet formation methods. Comparison of fiber orientation distributions reflects vectors of hydrodynamic forces and the fiber-fiber interactions arising during sheet formation process, contributing to a varying degree to each of these techniques. Samples manufactured by dipping exhibit more fibers oriented in the direction of gravitational forces of water drainage, samples produced by scooping method show tendency of the fibers to orient themselves along the direction of the laminar flow on the surface of the sieve, while samples manufactured by pouring are characterized by greatest orientation variability among the three groups.

These results show how scanning SAXS can be applied to paper artifacts to aid in papermaking technology identification, providing very high-resolution data, collected in a relatively short time.