Lincoln Charter Project
Lincoln Guildhall and University of Lincoln
Condition
The 1456 Charter of Henry VI is a significant document among the Charters Collection of Lincoln Guildhall. It consists of a sheepskin parchment containing text in iron-gall ink and pencil, with a repaired double sided Royal Seal in green wax attached to the parchment by a plaited cord of dyed natural fibre and metallic thread.
The manuscript and its components were in a fragile but structurally stable condition and safe for careful handling.
Analysis Aim
Collaborative non-destructive material analysis of 15th C manuscript and seal to reveal relevant details about the object for dissemination to conservators, historians and a public audience.
Analysis Results
Metallic Threads
XRF analysis and optical microscopy of the metallic threads and their corrosion products indicated a thinly gilded copper alloy. The threads were most likely manufactured by hammering gilded wire into strips before coiling it around an undyed yarn.
Wax Seal
XRF analysis and X-radiograph of the wax seal revealed the use of Verdigris pigment to tint the wax seal, as well as confirming the ink to be iron-gall ink. The x-radiograph also revealed the use of sewing needles to support previous repairs thought to date to 1788.
Natural Fibres
Optical microscopy and comparative analysis revealed the natural fibres as linen, most likely glass polished to provide a silk like sheen. As well as indicating the parchment to be of sheepskin.
Digitisation
RTI images of both faces of the wax seal and its cords were produced using RTIBuilder 2.0.2 and uploaded to the visual media service, Ariadne for public dissemination.
Digital 3D models of the Charter were produced using photogrammetry processed through Agisoft Metashape 1.5.1
