21 April 2010
Reason for treatment
Remove Plaster of Paris surround, investigate removal of coating, re-secure flaking paint, consolidate backing as necessary, remount.G H
See also publications:Treatment of an 18th dyn wall painting fragment at the British Museum. j. Dinsmore & H. Howard:(Conservation of Ancient Egyptian Materials. UKIC Archaeology section 1988.London.) & The Tomb of a scribe & counter of grain: Lisa Manniche:( Lost Tombs. KPI 1988 London ) The fragment is set in plaster of paris in a inner wooden frame covered with a wooden veneer. The front of the frame was glazed. Plaster of paris completly covers the silt/straw backing of the fragment and in some area extends over original surface of the wallpainting. The backing was found to be friable in places.The perimeter of the painting had been coated with a water soluble coating applied during a previous treatment it has now yellowed and in some areas contracted is causing cupping and flaking of the water sensitive paint layer. In places it had also caused lifting of the underlying ground with the paint layer. The consolidant was applied in a band around the perimeter of the fragment. Where it was thickly applied the coating has craquelured.The central portion of the painting is in good condition save for a few small loose flakes. Disruption of the paint layer and ground is particularly notable for the first 5/6cms around the edge. A yellow staining of the ground was noticed in this region. Possibly a result of the water penetration from the plaster of paris during mounting.
The glass front and veneer were removed. The edge of the fragment was faced with acid free tissue adhered with Mowital B30H (polyvinyl butyral) 2.5% in IMS.The plaster of paris was removed down to the bottom edge of the silt/straw backing. The silt/straw backing was consolidated with Mowital B30H (polyvinyl butyral) in 5% IMS applied with pipette. Great difficulty experienced in subsequently removing facing. Acetone:IMS (50:50) effective but considerable care had to be taken to avoid lifting flakes along with acid free tissue. RELAYING PAINT FLAKES;(Method 1) Previously prepared film of Raccanello acrylic silane (paraloid B67-polyisobutylmethacrylate,B72-ethyl methacrylate,methyl phenyl silicione resin,trichloroethane) was used Small pieces of film were slipped beneath the flake. A drop of acetone dissolved the resin and the flake could be relaxed with the heated spatula applied over an intervention layer of silicon paper. (Method 2) Mowital B30H (polyvinyl butyral) 2.5%-5% in IMS introduced with a fine brush was used to consolidate powdery and disrupted areas of paint and substrate. After consolidation the area was cleaned with acetone/distilled water 50;50. The coating swelled in some areas. Other coated areas were treated with warm water. Acetone or acetone;distilled water was then used to lift the swollen coating from the paint layer.(Method 3)Paraloid B72 (ethyl methacrylate copolymer) 2-5% in 2 ethoxy ethanol or xylene introduced to powdery and tiny flakes. Flakes relaid with a Heated spatula and silicone paper. Flakes which could not be relayed were supported with a filling made from Mowital B30H (polyvinyl butyral) 10-30% in IMS and gilders whiting toned to appropriate colour with Caen stone dust and raw umber pigment powder. The fillings were bevelled in towards the fragment.(Experiment carried out using PVB and Barium sulphate toned to match the render. This should become visible under UV light and differentiate with original. REMOVAL OF COATING:Samples of the surface coating were taken for XRF analysis. SEE DIAGRAM) The surface coating was removed to the extent possible by swelling with hot water and gently removing with brush or small swabs and acetone; d.water (50/50) Conservation work undertaken by H.Howard & J.Dinsmore. 1987-1992 Conservation work undertaken by K. Hignett 1996-1997. Over the years the paint layer had become very dusty, albeit covered most of the time. The dust was removed with soft sable brushes and Wishab sponge (vulcanized latex,filler). An area of lifting paint in the top register of the wallpainting had not yet been consolidated, it exhibited a thick layer of coating