Materials on Conservation

4th international Round Table of seal conservators

On the 4 June 2016, our SIGILLVM Board Members Agnès Prévost and Marie-Adélaïde Nielen from the National Archives in Paris, convened a round-table meeting of seal conservators to discuss current issues on the preservation and storage of seal impressions and casts. The following report details the contributions from the speakers.

Read the report [PDF, 655KB]

Provenance and Season of Production of Beeswax

Beeswax was mainly used for the production of wax candles, as wax candles produced less fatty smoke than candles made of animal fat. During the burning of the candles the beeswax burnt up. Only a small part of the beeswax was saved up in seals and an even smaller part in pieces of art. The provenance of beeswax can be established by searching for and identifying of pollen grains. If these grains are identified as produced by heath plants (Calluna vulgaris) one may conclude that the beehive stood on or near a field of flowering heath plants. However, for The Netherlands holds that in the 17th-18th centuries much beeswax was imported from Baltic countries. Would it be possible to identify the region and the time of the year of the beeswax production?

This question was positively answered by Carol A. Furness (The extraction and identification of pollen grains from a beeswax statue. Grana 33 (1994): 49-52), who investigated the pollen grains in a waxen statue attributed to Michelangelo (1475-1564). Carol Furness found pollen grains of plants growing in the coastal areas of the Mediterranean. Maybe Michelangelo obtained wax produced in the neighbourhood his Italian studio. So, on the basis of the pollen grains in the beeswax it is possible to locate the region of wax production and the period of the year of collecting. I am searching for similar papers as the one by Carol Furness reporting the provenance of wax for wax seals impressed in the 16th-17th centuries. The investigation of seals by tomography, a method borrowed from medical research, is known to me.

Anton C. Zeven, NL-Wassenaar August 2016.


Les Sciences à l'heure médiévale

A podcast from Les Rendez-vous de l’histoire featuring Agnes Prevost discussing methods of scientific investigation and conservation of historical documents and seals.

Une plongée dans les sciences utilisées pour mener des investigations et faire ressurgir les secrets du passé contenus dans des objets médiévaux : étude des processus d’oxydation et de corrosion, analyse des encres, recherche des ADN sur des poils ou des cheveux.

Listen to the podcast.

Deterioration of white wax seals

The question posed by P. R. Eley was - "From the experience of conserving many hundreds of wax seals, why do uncoloured medieval seals appear less stable than those seals that are coloured? Rarely have I come across a good intact uncoloured seal, they tend to be unstable and rather crumbly and need much care in handling, whereas virtually all the coloured seals are robust and remarkably intact."

Read our members' replies here (PDF, 499 KB)