Historic Churches 2020

22 BCD SPECIAL REPORT ON HISTORIC CHURCHES 27 TH ANNUAL EDITION lasted for more than six months and at its peak 17 conservators and interns were conserving the ceilings, with at least another six working to remove paint from bricks in the undercroft, re- pointing the exterior, and undertaking stone repairs and other works. CONSERVATION OF THE CEILINGS A large part of the conservation project focused on cleaning and conserving the painted ceilings in the nave and chancel. The nave ceiling is divided into 24 bays, 12 on the north and 12 on the south side. Each of these is divided into an upper and lower tier, with painted timber ribs separating the bays. The timber ceiling is painted with bold, floral motifs using stencils, while 72 busts of saints have been painted on canvas and adhered to the substrate. These canvas paintings, or marouflage, depict female saints on the north side, and male saints on the south. The chancel ceiling is strikingly different from the nave in form and style, with painted plaster spandrels separated by stone ribs: groups of saints are depicted at the east end, flanking the figure of Christ above the altar, while angels decorate the west end of the chancel. Here the style of painting is more delicate and narrative compared to the bold, almost cartoon-like design in the nave. Both ceilings had received layers of varnish over the years which had yellowed with age and was now obscuring the paintings. In the case of the nave there was an even older organic varnish which had now turned dark brown. This was still visible on the ribs but it had been partially removed from the painted bays using cleaning materials that had adversely affected the paint layers, leaving numerous drips and losses. There is no record of when this cleaning intervention took place, but it seems likely that a modern synthetic varnish was applied over the bays at the same time. The same yellowed modern varnish covered the chancel ceiling too. Varnish removals and reductions Cliveden Conservation undertook a condition assessment of both ceilings and conducted a series of treatment trials, focusing on removing the deteriorated varnish. The most challenging aspect of this removal was finding materials that solubilised the varnish but not the paint layer below. A range of solvents and cleaning agents were trialled, beginning with the least hazardous and the lowest concentrations of materials, before gradually progressing through the available options. It was found that the method of delivering the cleaning agents was just as important as the selection of active materials themselves. This was particularly true across the chancel ceiling, where the plaster substrate had been left intentionally uneven in order to reduce glare on the paintings from candlelight. This uneven surface meant that varnish and dirt collected in the troughs and made swabbing incredibly difficult. A selection of gelling agents, poultices and sponges were trialled to determine how best to apply conservation materials; each was held against the surface to maximise its cleaning action, while clearing the solubilised varnish and dirt from the surface with minimal mechanical action. Various materials and methods were developed to address the organic and synthetic varnish layers of the nave. Different approaches were taken for each ceiling: in the nave, the oldest organic varnish was removed from the ribs using low concentrations of alkaline cleaning agent. This was typically applied using conservation sponges; however, where the varnish was thick and less easily removed, xanthan gum was added to form a gel which could then be left on the surface for a short period of time to increase efficacy. The yellowed synthetic varnish that covered the painted wood and marouflage saints was extremely difficult to remove. It did not respond to most cleaning agents; some solvents caused whitening of the surface and others solubilised the paint layers almost immediately on contact. After extensive trials a mixture of benzyl alcohol and white spirit was finally selected. This was applied using xanthan gum to create a semi-viscous gel that could be left on until the varnish became grey and began to shrink away from the surface, at which point it could be carefully brushed or swabbed away. Due to the sensitivity of the paint layer, the treatment was timed to ensure that the solvent did not dwell for too long on the surface. However, it was primarily down to the skill of the conservators to monitor and remove the varnish at the optimal moment. Removing varnish from 72 marouflage saints was a huge undertaking. These paintings had been executed off site and then adhered to the substrate using adhesive and small nails. Although they were created using templates, the placement of the figures and the Top, the chancel ceiling after conservation (Photo: Anthony Coleman) and, below, a conservator reducing the layers of varnish as it was not possible to remove all the layers without damaging the painted surface beneath