Conservation of objects and wall paintings (Julie Dawson)
The work described in this section took place between 26th September and 2nd October 2000. The conservation work which had been started in the previous season on the linen shroud inscribed with texts from the Book of the Dead was completed. A group of small fragments and one large, badly crumpled piece were treated. The large fragment has an original fold down its centre (which was preserved so far as possible during the conservation treatment). The textile is particularly badly deteriorated to either side of this fold with many holes. The linen is generally dark with areas of staining and the fibres are brittle and friable. There was loose dirt in the folds and many small, crushed fragments of fabric. The red and black text is well preserved, but in places very difficult to see on the dark textile.
A humidity chamber was constructed to allow the textiles to take up moisture vapour and gradually to relax the fibres. When the textiles were sufficiently supple, as many creases as possible were eased out, the weave re-aligned and held in position with light weights. Loose dirt was picked off the surface and a few small repairs were made using tabs of Japanese tissue held in place with 4% Methocel AC4 (methyl cellulose adhesive) in distilled water. Brittle, powdering fibres were consolidated with 2% Klucel (hydroxy propyl cellulose) in alcohol, applied from a small brush.
The large piece and its associated fragments were laid on an archival-quality, fabric-covered board. A few irregularly sections of the edge were held lightly in place with Japanese tissue tabs attached to the back of the textile and to the support with 4% Methocel AC4.
A conservation-quality box was constructed to hold the linen and its support board securely. The group of small fragments was mounted after treatment in a folder (see 1999 report) with a fine nylon net window over the top of the pieces, through which they can be studied without disturbance.
The packing of several textiles conserved in previous years was modified to ensure that they can be stored safely in the long term.
A condition report was made on a few sections of the wall paintings which had not previously been examined and part of the heavily soot-stained ceiling in the front room was lightly cleaned with a Wishab (dry, vulcanised latex) sponge.
The condition of the tomb structure, wall paintings and objects in long-term storage in the chambers and shafts may all be influenced by the environment inside the tomb. The detrimental effects of environment instability, especially related to the incursion of large numbers of visitors, has long been a cause of concern in the tombs of the Theban Necropolis. A few detailed studies have been published, for example of the conditions inside the tomb of Nefertari. In tt 99 we are interested in logging the environment of a tomb which is closed (but not sealed as the old iron doors are loosely fitted and have a series of intentional small holes in them) for most of the year and which does not appear to be suffering serious on-going deterioration. We also wish to see the effect of the Mission's annual season during which the tomb is open and occupied by members of the team for six to seven hours a day.
It was not possible to start logging until the 1999 season and only a very limited amount of equipment has been available for the study. Two Hanwell Humbug data loggers (one MK II and one MK III) are being used to record temperature and relative humidity. With occasional interruptions (removal to the expedition's base for downloading or movement to different areas of the tomb for experimental purposes) the MK II logger has been in the front room of the tomb (in the niche in wall 5) since 1 December 1999 and the MK III logger in the central niche in the rear room since 16 December 1999. Data for the front room is currently available for the entire 1999 season, the subsequent closed period in the tomb and the first 9 days (23 September to 2 October) of the 2000 season. The logger in the rear room ceased to record on 4 March 2000 and was checked and set logging again on 27 September 2000.
The logging interval has generally been set to every half hour during the active season and every one and a half hours during the undisturbed closed period. The observations and conclusions which may be made from such basic data are strictly limited and need to be set in the context of the weather conditions through the same period once this information has been obtained.
Overall, not surprisingly, the climate inside the closed-up tomb is hot, dry and stable, showing in the front room small diurnal fluctuations (maximum 0.5° C and 3.5% RH (relative humidity) and a gradual shift over the period from January to September from 27°C to 31°C and between about 16% RH and 22% RH (see, for example, chart for June 2000). The rear room shows the same pattern but both the diurnal fluctuation and seasonal change are minimal. The shafts in the rear room provide an extremely stable environment for the storage of the excavated objects.
The Mission's season has quite a dramatic effect, more so of course in the cooler, more humid December weather than in September. The opening of the doors in the early morning each day causes an immediate drop in temperature of up to 5° C and an accompanying rise in relative humidity of up to 11% RH with a rapid recovery in the first 2-3 hours, followed by a more gradual recovery for the rest of the day and a return over night to the long-term closed conditions (see chart for 26 December 1999 to 1 January 2000). However, there is also a small cumulative effect on the level of humidity with a gradual rise over the course of several days in the base-line relative humidity to which the closed tomb reverts at night. Again, in the back of the tomb the changes are mirrored but to a lesser degree.
Further data will be available when the loggers are downloaded at the start of the next season.