The Challenge of Making Imperfect Paper

On the surface, paper looks like a very simple material. On closer inspection, however, it turns out to be one of the most complex writing supports. A number of different techniques and technologies have been used to make paper at different times and in different places. In the age of industrial papermaking, many traditional papermaking workshops have been marginalised and knowledge of the techniques they developed has been lost.

At the CSMC, Agnieszka Helman-Ważny and Malgorzata Grzelec want to promote our understanding of the different technologies used to make paper, particularly in Asia. To this end, they are working together with Sylvio Haas at the DESY synchrotron facility. In their joint project on ‘Measurements of Paper Components’ (RFA20), they want to develop X-ray scattering techniques to interpret the spectral features that reflect the manufacturing processes in different papermaking technologies. This, in turn, requires a thorough understanding of the parameters involved in the production of paper.

Together with Gangolf Ulbricht, a Berlin-based papermaker, the researchers are reconstructing historical papermaking technologies. Using these technologies, they are designing and producing a series of paper samples to study the complex interplay of multiple papermaking parameters in a controlled environment. In order to understand how certain steps in the production process affect the paper produced, they have developed a statistical model derived from materials engineering applications to account for all possible combinations of parameters. Using this approach, they also generated a set of samples that included combinations of processes and materials that had never been used together.

The experiment controls for the influence of several factors, such as the type of raw material, the method of paper sheet formation, and the impact of formation aids on the structural characteristics of the paper. The resulting set includes more than 100 samples whose physical properties differ significantly, providing insights into the role of particular steps in the manufacturing process. One notable example is the addition of plant mucilage, a formation aid that was used in China, Korea, and Japan in a sheet formation technique known as scooping (called nagashi-zuki in Japan), which increased the viscosity of the papermaking fluid and as a result improved the uniformity of the distribution of paper fibers. A comparison of sheets produced with and without the mucilage shows the importance of this technological advance in the development of Asian papermaking and the considerable insight of the ancient papermakers into the physics and fluid dynamics of fibre suspensions.

The samples collected will form a repository of materials for the technological study of historical papermaking developments. They will then be measured at the DESY synchrotron facility to create a reference database of X-ray scattering spectra.