Digitalization and Preservation of the seals
Some examples from the Archives of the Bohemian Crown
By Libuše Holakovská
The charters and seals of the Archives of the Bohemian Crown (AČK) are given – due to their significance – an extraordinary attention by the archivists and conservators. The department of the physical care of records I work for, ensures the safety of this fond’s charters in the course of all extraordinary events related to it. The extensive digitizing, my colleagues have mentioned, is no exception. The conservator’s assistance during the digitizing of seals is as self-evident as it was during the digitizing of the AČK charters within the Monasterium framework in 2007.
At the same time, it’s a unique opportunity for the conservators to conduct a thorough research of the current condition of the seals appearing on this fond’s charters. In the course of the digitising process, the conservator helps to ensure the transportation of the charters from the vault room and back, is responsible for taking out the charters of their packaging, assists the photographer, ensures optimum climate in the digitising rooms, and puts in data on the condition of the seals and their pendants into prepared forms.
The history of the AČK fond storage is very rich. Although the storage of charters, that are part of the national treasure, was always given an extraordinary attention, often they were deposited in unsuitable conditions. The safety of the deposition of the records was always emphasized. However, the safety concerned the security against theft rather than safe storage. High humidity, variable temperatures or unsuitable handling led to damage of of charters and seals.
It was not until the fond was proclaimed the Archival Cultural Heritage (in 1977), and later the National Cultural Heritage (in 1988) that the proper and safe storage was ensured. At that time, the safety of the physical state of the AČK was tackled in its complexity. Such storage conditions that do not allow degradation of documents and allow their natural aging to be slowed down to minimum were set up for the fond, and started to be enforced on a regular basis.
In 1986, a vault room was designed, and the AČK was placed in it later. Because of the fond’s exceptional significance, and since its direct research use was ruled out, the original plan called for an atmosphere with 10 more or les 1 °C temperature, and relative humidity of 55 ± 2%. In this was an atmosphere with less oxygen was being considered too. These plans have been implemented slightly changed. The vault room is now being air-conditioned as the other depositories at the 15 more or les 2 °C temperature, and relative air humidity of 55 ± 5 %.The air-conditioning unit of the vault room is equipped with special filters that eliminate air pollutants, and ensure the air quality appropriate for long-term storage of archival records.
As long as the parchment charters are stored in a suitable environment, the parchment resistance against aging is very good. Any long-term increase in relative humidity of the environment above 70 % at 20°C is dangerous for the parchment. Under these conditions, there is hydrolysis of parchment, and microbial corosion occurring.
Long-term overdrying leads to the increase in hardness and parchment fragility. Frequent fluctuations of relative humidity lead primarily to the damage of the coloured layer.
Negative influence of light on the parchment and recording tools should not be underestaimated either. Therefore, during the digitizing process, the charters are taken out of the vault room for the shortest necessary time. Thus far, I have discussed mainly the possible ways of parchment damage.
Now, I will focus on the seals. The seals of the AČK are made of beeswax most of the time. Papal charters usually contain leaden bulls, the most significant charters contain golden bulls. The aging of the beeswax happens relatively slowly; however, in the aging process, the wax undergoes a number of changes that affect its properties. Mostly, wax seals suffer from mechanical impairments. In the 80’s, over 1000 seals underwent conservation. Wax seals required cleaning, some needed disinfection or impregnation. The broken seals were re-assembled and completed or their broken edges were repaired. Some metal seals required cleaning and passivating. We believe that at this moment, most seals are in a stabilized condition.
On the other hand, some pendants, especially the textile ones, are in a bad state. Some seals were torn away, and attached to the charters.
The charters have to be handled very carefully in order to prevent the pendant’s impairment.
The charters of the fond are currently deposited in a vertical position. This storage method is named by its creator, a Dutch archivist M. P. van Buijtenen, “Buijtenen system”. It was chosen for the AČK charters in the second half of the 1980’s, in the same period when the new vault room was built. This vertical system of storage calls for each charter to be hung separately in a special “pocket” having been created by folding a strip of Melinex foil.
The loose ends of the foil and the top end of the charter are pressed between a plastic hanger and a transparent trim, the grip is secured by brass screws. In the pocket, the seals are held by plastic scippets that are welded up to the back side of the pocket by an ultrasound welder. There are openings for seal pendants created in sides of the plastic scippets. Thanks to these scippets, the pendants are not excessively strained, and the seals are protected against mechanical harm. The pockets are hung into special rod racks with the hangers.
Charters with a larger number of seals with varying lenghts of pendants or charters with heavy seals are placed in a horizontal position into custom-made flat boxes. A flatted-out charter in the box is snapped with distachable melinex strips. The seal or seals are protected by a carton box made to fit the seal’s size and shape.
Ten or more charters are taken out of the vault room. They are hung on a stand designed for this purpose. Then, the charters are individually produced from the melinex scippets. The removal is done by loosening up the brass screws on the hanger of the melinex pocket, and careful removal of the seal from the skippet. After the description of the charter has been checked for accuracy, the seal is thoroughly examined by the conservator, and the gathered information is written down in prepared form. The form is created in the Excel spreadsheet.
The following data are entered for each seal: charter identification number (signature), seal order on the charter, seal material (wax, Spanish wax, gold, plumb), the way the seal is appended (parchment, textile, purl, applied seal), and whether the seal was protected by a box in the past.
Later, all data related to the previous conservation will be entered into the questionnaire (year of conservation, cleaning with venetian soap, securing the fractured surface, joining of fragments, supplements, removal of wax effloresences, propolis application, disinfection). Next, we examine seal damage observed in 2015-1? (p.e) – (cracks, breakage, loss, so called wax dessication, wax effloresences on supplements, wax effloresences on historic wax, corosion of metal seals).
Let me digress here, and explain the terms I’m using:
Dessication – wax is getting fragile, and is loosing its plasticity, becomes more brittle, and changes its color. It becomes lighter in colour. This problem was eliminated back in the 80’s by impregnating seals with propolis. The propolis coat consolidated the seal very well. Now, there are no signs of worsening of the condition.
Wax effloresences / white crystallic coat clinging to the wax surface. Most often it is created on supplements, however it occurs also on the surface of the historic wax. This layer can be removed dry, mechanically with a brush or cotton swab. As this layer is not aesthetically desirable, we also remove it in the digitised seals.
Once the questionnaire is filled out, the charter and the seal are handed to a photographer who takes a picture of the seal design. After the seal has been photographed, the charter goes to the archivists – historians who describe it.
After that, the charter is again returned to the melinex pocket, and put in its original place in the vault room.
The digitizing of the AČK fond seals has been taking place over a year. During this time, no damage to the seal has occurred. The cooperation of specialists of various fields – archivists and conservators, is very beneficial for this project. Also, it guarantees the safety of the charters and seals of the fond. The cooperation ensures efficiency of work, and minimazes the handling time of the charters, and their stay out of the vault room.
All images are property of the author.
Mgr. Libuše Holakovská is working as conservator of the National Archives in Prague.