What is my Written Artefact made of?
Characterisation and classification of materials
Stylianos Aspiotis, Anna Schulz
The study of materials used to produce WAs is the starting point of the profiling activity. The first step consists of identifying features of the materials and classifying them accordingly in existing typologies. Characterising features are the chemical, biological and physical properties of a material, i.e. their composition and the ways in which they behave under certain conditions, that can be observed and measured through a variety of analytical methods.
The scope of such an analysis varies according to different research aims. It can thus range from the study of a single WA (or its fragments) to the types of materials that are used for its preparation (in a given culture, for example). More specific research questions may concern:
- search for specific features or patterns of features that relate to broad historical and cultural contexts in which WAs have been produced and used. Examples:
- study the technical evolution of paper and its commerce according to the spreading of different types of papers for WAs - types based, for instance, on the detection of the sieve pattern and the identification of the fibers used for its production.
- characterising the animals (incl. species, breed, sex, disease) used to produce parchment employed in WAs by means of genomics and proteomics.
- search for commonalities and differences of material features that characterise the production and use of a specific WA or a well defined group of WAs. Examples:
- analyse the black ink types and colour substances (pigments and dyes with an array of methods (NIR and UV reflectography, XRF, Raman spectroscopy, FTIR spectroscopy, ASAP-MS)) to observe if in a WA only one or multiple media are present, in order to reconstruct the history (e.g. writing processes) of the WA.
- Material profiling of cultural-heritage objects such as engraved gems and cylinder seals by Raman and infrared-reflectance spectroscopy that along with traditional gemological methods can assist in the unambiguous identification of the consisting mineral-phases; an aspect that can lead to the provenience of the inscribed gems.