Materials
Given the immense variety of material involved in written artefacts, the purpose of this section is only to give an overview of the different materials and their chemical and physical properties. The Guide makes a distinction between writing supports, substances, and implements. Writing supports, for example, range from materials used to create small, portable objects (e.g., parchment, paper, palm leaves) to those used for large installations (e.g., gravestones, monuments, mountainside inscriptions). Writing substances include any additional substances, such as an ink or pigment, that are applied to the writing support in order to produce visible writing. Writing instruments include any object used to apply a writing substance to the writing support (e.g., brushes, quills, pencils, printing blocks), as well as incision and carving instruments that are used directly on the writing support to transform it into a written artefact. The Guide also considers digital images to be a kind of material, inasmuch as they have unique compositional properties and can undergo different types of analysis.