Portraits (oils)

The Portrait Project

Recent initiatives have included employing a paintings conservator to carry out a condition survey of the Library's paintings. The Portrait Project was already underway with the initial work of drawing together information about the works of art and creating a temporary storage for this collection which offered acceptable conditions. Supported by a skilled volunteer, the library's conservator has been listing and identifying the approximately 300 paintings in our collection. Procedures have been introduced to safeguard the works of art. A room, with an acceptable environment for oil paintings, will be dedicated to the portraits. A rolling unit (given by the Bodleian Library) has been assembled. The conservator is also working with a team of specialist photograpers who are photographing the collection.

Ruth Bubb examining one of the Dr Williams's Library portraits.

Issac Watts

Ruth Bubb Ltd

Portrait of Isaac Watts
c. 1700
h 757 x w 640 x d 19 mm
Oil on canvas
Inscr. in paint to the left of the sitter’s head ‘Isaac Watts, D.D | 1674-1748.’
Stamped into reverse of vertical stretcher cross member ‘F. Leedham | Liner’
Printed label on vertical stretcher cross member ‘32’
Printed label on right (back) stretcher member, under gummed paper framing, tape ‘805’
Handwritten circular label on left (back) stretcher member‘96’
Inscr. in black chalk on gummed paper framing tape, on upper frame member, illegible.
See condition survey of 1st September 2016.
The darker blues on the sitter’s jacket were observed during cleaning to have a blotchy appearance. This could indicate that they contain smalt, a pigment consisting of ground
Ref: DWL.1602 30th July 2018

cobalt-containing potassium glass that, when bound in oil, has been observed to discolour.1 Technical analyses would be necessary to confirm this hypothesis. The darkest shadows in the drapery are very thinly painted, and possibly also abraded by previous treatment, so that the brown colour of the ground layer is visible through the black paint.

The painting was removed from the frame. The reverse of the canvas was cleaned by brushing and vacuuming, followed by a vulcanised rubber ‘Smoke Sponge’. Debris was removed from behind the lower stretcher bar with a nylon spatula. The front of the painting was surface cleaned with a 2% solution of triammonium citrate in deionised water, cleared with tap water. Old discoloured varnish was removed with acetone. The thickest parts of the overpaint on the right side of the background were partially removed with ‘Nitromors Varnish and Lacquer Remover TM’ (dichloromethane and methanol in a thixotropic gel), cleared with acetone. The overpaint was further removed mechanically with a scalpel under magnification. It was not possible to remove the most resilient parts of the overpaint without risk to the original paint. It was therefore decided to retain the residues and adjust their appearance by retouching.
The labels on the reverse of the stretcher were protected with 125μ ‘Melinex’ archival polyester film, attached with galvanized staples, prior to lining. The inscription on the gummed brown paper tape was removed from the reverse of the frame with moisture, washed and lined onto Japanese ‘Kozu’ paper with sodium carboxymethyl cellulose adhesive and placed in an archival polyester pocket.
The canvas was relined with ‘BEVA 371’ (ethylene vinyl acetate co-polymer) heatseal adhesive onto linen canvas and restretched with copper tacks onto the existing stretcher. The missing expansion keys were replaced and all the expansion keys were secured with nylon line. After lining, excess adhesive was removed from the surface of the painting with white spirit. An isolating varnish of ‘Paraloid B72’ acrylic resin 15% in ‘Shellsol A®’2was applied by brushing. Losses in the paint and ground layers were filled with ‘Flügger’ acrylic putty (chalk and butyl methacrylate dispersion). Retouching was carried out with dry pigments bound in ‘Paraloid B72’ acrylic resin in 1-methoxypropan-2-ol. A final varnish of ‘Laropal A
1 Mühlethaler, B, Thissen, J, ‘Smalt’ in Roy, A, ed. Artists’ Pigments, A Handbook of their History and Characteristics, Vol. 2 National Gallery of Art, Washington, 1993 pp. 113, 116
2 Aromatic hydrocarbon solvent consisting mainly of low boiling point naphtha and 1,2,4 –trimethylbenzene. CAS No 64742-95-6
Ruth Bubb Conservation of Paintings - 2 - July 2018

81’ low molecular weight aldehyde resin 25% in 65% ‘Shellsol D40®’ 3 and 35% ‘Shellsol A®’ was applied by brushing. Retouchings were adjusted as necessary with dry pigments bound in the same.
The frame was treated by a frame conservator. The frame was surface cleaned with moisture. The surface of the outer frame and inner gilded slip frame was consolidated with rabbit skin glue. Surface losses were filled with gilders’ putty (chalk and animal glue and retouched with ‘Plaka’ casein paint and wax. The old gummed paper framing tape was removed from the reverse.
The rebate depth of the frame was built up on the reverse with mitred softwood strips, attached with brass screws. The frame rebate was lined with gummed brown paper tape. 3mm ‘Optium Museum Acrylic®’ was fitted into the frame and dust-sealed with ‘Scotch® MagicTM Tape’. The existing inner gilded slip frame was fitted behind the glass to separate the painting from the glass. The opening of the slip frame was too tight for the painting after lining, because of the increased bulk of canvas around the edges. It was necessary to remove some material from the rebate walls by chiselling and sanding in order to achieve a satisfactory fit. The slip frame was secured in the frame with gummed brown paper tape and lined with wool felt with pressure sensitive adhesive, to cushion the surface of the painting. It was spaced in the frame with balsa blocks, attached to the sides of the frame rebate with ‘Conservation Adhesive’ (Paraloid B72 acrylic resin in acetone), and secured with screwed brass mirror plates.
The painting was secured in the slip frame with screwed brass strips. A lightweight backing of 125μ ‘Melinex’ archival polyester film was attached to the frame with galvanized staples and sealed with ‘Filmoplast P90’ archival paper tape with acrylic adhesive, applied over gummed brown paper tape as a release layer. The pocket containing the conserved inscription on gummed paper framing tape was attached to the backing with double sided acrylic pressure sensitive tape.
3 Low aromatic hydrogenated solvent consisting predominantly of C9- C11 paraffins and naphthenes CAS No 64742-48-9
Ruth Bubb Conservation of Paintings - 3 - July 2018