 |
Holy
Trinity Church Coventry's History Pages .....Sarah
and Andrew invite you to.... come in
and "take a pew"...... |
 |
|
|
|
GRANVILLE
& BURBIDGE
Following a lengthy genesis, the cleaning of the painting began in earnest on 2nd September. This brief interim account, the first of many monthly reports, documents the progress of the treatment and the main points of interest raised during the exposure of the underlying painting. Prior to the beginning of the treatment, copies of a selection of previous reports were sent to all members of the *team to help with their familiarization and induction to the project. Dr Nicholas Eastaugh, conservation scientist, was commissioned to provide a database of cross sectional images of previously collected paint samples. He was also instructed to supply a system for identifying each sample, to provide a means of adding observational notes to the data base, and to enable the regular updating of the database with new information from any further samples collected. In addition, the paint samples were to be reviewed and this would include the identification of the statigraphic layers of samples (materials, thickness, etc), a review of samples where materials were added; ie, identifying the characteristics of Gee's restoration and any other interventions and to flag any anomalies that may effect the cleaning regime, or would be worthwhile investigating further. During the first week, the working environment was established on the upper two levels of the scaffold. An office area was also established on the 2nd from top level, where a computer notebook containing the database was installed. A telephone line was provided to give, in addition, access to internet facilities. Some modifications were necessary to the scaffold floor to enable the smooth operation of the castors on the pillar mounted binocular microscope, and to prevent the leading edge of the floor coming into contact with the face of the painting. Also, some modifications were made to enable greater flexibility with the background lighting. Throughout the setting-up of site, due attention was paid to relative health and safety issues. Owing to the complexities of the investigation and treatment of the wall painting, and the unfamiliarity with the database, it was considered essential that the team was given a thorough introduction to these before becoming involved in the practical side of the work. Copies of previous reports were made available and there was a discussion about the development of the project, and how the treatment methodology was eventually established. Dr Eastaugh visited the site and gave a thorough explanation of the analytical aspects of the project and demonstrated the use of the database. An essential component for the documentation was the production of a grid system for the painting. This system is now being used to locate samples, identify areas being photographed and documented. 5.1 Photography During the treatment regular photography was undertaken to document aspects of the paint technique, condition etc, that was considered of relevance. This was using a Minolta X-700 SLR camera fitted with macro or wide angle lens, and using slide film (Fujichrome Sensia 100 ASA) . The lighting was with tungsten lamps using a blue filter (Hova 80B). As part of the processing, a CD-Rom of the images was provided. In addition a professional photographer was commissioned to undertake overall photographs in tungsten light (using Jessops 80A blue filter) and u.v light (using Wratten filter No2e), in slide and negative format using a Leica R6 and R3 SLR camera. 6. TREATMENT The treatment essentially follows the methodology set out in the report produced on completion of the large cleaning tests in 2001, and to date has focused around the test areas on the wall painting. 6.1 Stabilizing paint plaster and stone. Where the paint layer is unstable this is treated with isinglass+ deionised water (1.20w/v) applied warm. A few drops of industrial methylated spirits (IMS) are added on the application of this: in small localized areas of disruption, the glue is applied directly to individual flakes of paint. In larger areas of disruption, a number of applications are necessary, and frequently this is through an intervention layer of lens tissue. Flaking paint is pushed back through the lens tissue, or lese through an intervention layer of polyester film (MelinexTM). In some cases during the initial stabilizing procedure, the tissue will be allowed to dry on the surface before being removed using cotton wool swabs dampened with deionised water. Residue glue is removed using similarly dampened swabs. All stabilization with isinglass has been before or during the cleaning procedure.
A small section of loose stone was fixed with an acrylic dispersion. 6.2 This is accomplished using IMS, either pure, or with a few drops of white spirit added to reduce evaporation and improve its handling properties, and repeatedly applied using small cotton swabs. To some degree the use of spot poultices made from cellulose powder and IMS has been successful in reducing isolated islands of coating. Greater success in evenly reducing the coating, particularly where there were areas of dense craquelure and/or "balling" of the coating was achieved by scraping back the surface after initial swelling with IMS. This operation had the twofold effect of reducing/removing the dense and insoluble crust and exposing the megilp, and spreading this mixture into the crevices of the craquelure. The overall effect was to produce a controlled and relatively even reduction of the coating. Throughout the operation a binocular microscope (x5-20 mag.), magnifying glasses (x2-3.5 mag.( and a u.v. light were used to verify the level of cleaning. The level of cleaning is reducing the bulk of the megilp but still leaves scope for a second phase of cleaning, although this is most likely to be localized. As previously mentioned, Dr Nicholas Eastaugh provided essential support during the preparation for this campaign of treatment. Once treatment was underway, this has continued. Dialogue was maintained about the use of the database and the interpretation of cross sections and the type of materials to be found on the wall painting. A number of samples were also collected for analysis to answer specific questions raised as a result of the cleaning process. Within a week of receiving these we obtained initial feed back, and soon after a CD-Rom with images of cross sections. Uncovering the painting has revealed, in a dramatic fashion, the remarkable extent to which this has survived. Whilst there are scattered losses, these are generally small, and so far, do not hinder the legibility and the strong impact of imagery. After an initial visit from Miriam Gill, her impression was that the painting remains consistent with her previous dating of between 14.0-40 and stylistically relates to the International Style found in Coventry glass in the first half of the 15th century. Most of the figures are outlined in black with the exception of the female figure visible in the previous cleaning test by Hulbert. Alongside a tonsured male she may be a donor, and for the moment her identity is speculative. The drapery has been depicted with tight folds often delineated in black, and full use has been made of modelling in glazes to create the illusion of volume. At this point there is still confusion over the extent of the intervention by the local artist David Gee in 1831. However, it would appear that his restoration includes black outlines (some have been found on traverse remaining islands of limewash - presumably first applied during the Reformation, c1560), and an area of red glazing (apostles in the top south corner) which is also upon what appears to be limewash. Beneath the main paint layer there is widespread evidence of another paint layer. The exact relationship between the main paint layer, and the fragmentary remains of an underlying layer, requires further investigation. The main paint layer may in fact be a restoration layer, repainting and reinforcing areas of the lost or diminished earliest paint layer. The stabilization of the paint with isinglass has worked successfully, and generally the cleaning has progressed smoothly. However, the rate of cleaning varies dramatically. This is mostly dependent upon the thickness and irregularity of the megilp layer. What appears to be a brown residue of the megilp layer which is resistant to the IMS has been found on some apparently random areas. This leaves a distinct pattern on the surface, and is particularly disturbing on pale colors. Some areas of red and some black lines have been found to be sensitive to the cleaning method. In some cases black lines, only visible in the i.r photographic survey, have been found to be highly sensitive to cleaning. The i.r photographic survey now displayed in an exhibition at the west end of the nave has been an extremely useful tool during the cleaning of these areas. A safe method to clean these areas is presently being investigated. Investigation of previously collected paint samples has revealed that there are layers common to the soffit and the wall painting, indicating that the painted decoration on these areas is coeval. The approximate area cleaned until 27th September was 37,660 cm squared. During the coming month the cleaning and stabilizing program will continue. A number of aspects of the cleaning which are currently of concern will be investigated. These include the brown residue and the leaning of the black lines and other colors which are susceptible to solvent action. Swabs will be examined for the pick-up of pigment, and samples will be taken for the examination of cross sections. The treatment of the brown residue may require further trials with additional solvents. Samples will also be taken to investigate the structure of the painting and to obtain a clearer picture of the sequence of paint layers in order to better understand their origins. A series of trials will be undertaken using solvents in thrixotropic gels to ascertain their effectiveness in safety removing the thick overpaint from the soffit. John Burbidge
*The following free lance conservators are contracted to assist with the treatment: Lucy Bunning, Toby Friedrich, Eva Gascon Pinedo, Andrew Hirst, Victor Hugo Lopez, Rachel Wit Granville & Burbidge, 111
Kingsmead Road, London, SW2 3HZ, Tel/Fax 020 8674 1969 |
|
Before leaving please sign our Guest
Book and let us have your comments and ideas! PLEASE NOTE: These are historic pages of Holy Trinity Church and the church interior may have changed since our photographs were taken as they do not post date 2005.
|