Joseph Blackburn
Hugh Jones, 1777
Technical Notes
The plain-weave canvas support is not lined. Selvage edges are present on both vertical tacking edges; the fabric width averages 105.5 centimeters from one selvage edge to the other. There are an average of fifteen warp threads per centimeter and nineteen weft threads per centimeter. Fiber analysis of a sample from the bottom tacking edge shows that the canvas is made of linen.
The tacking edges are intact, and there is cusping along the edges. The canvas, which is somewhat slack and undulated, has pronounced stretcher creases, including horizontal cross-member creases. Stains on the back of the canvas correspond to the crack pattern in the paint layers. A quilting effect on the back of the canvas corresponds to the network of cracks.
There are rust stains in the fabric of the tacking edges, caused by corrosion of the iron tacks. A fabric reinforcement has been glued to the back of the top-right corner of the canvas. Except where the fabric has been reinforced, the canvas apparently has never been removed from its original strainer. The strainer is constructed of Scots pine.1
Areas of localized reddish-brown paint that were applied to the back of the canvas correspond to the sitters face and hands.
The strainer has open mortise-and-tenon corner joints, with tenons running horizontally. Gauge lines are visible along the mortises, and the strainer members are tangentially cut. The cross-member also has mortise-and-tenon joins and is recessed from the canvas. The edges of the horizontal cross-member are beveled front and back. The hand-forged nails and upholsterers tacks on the tacking edges appear to be original. The strainer has sustained minor insect damage.
The ground is grayish white. The left and right tacking edges do not have ground on them, but the top and bottom ones do, suggesting that the canvas was commercially prepared. Evenly spaced holes that do not correspond to previous tacking holes are present 1.5 centimeters in from the selvage edge; they probably were made when the fabric was manufactured or when the ground layer was applied.
The ground was applied in a moderately thick layer that does not hide the canvas texture. There is low impasto in the white highlights. The background is thinly painted. The paint is thicker in the facial features, where the artist utilized a wet-on-wet technique. He seems to have used a glaze of a fugitive color on the tablecloth; areas of the tablecloth protected by the frame rabbet are a deep blue, while the exposed parts have faded to a dull green. The pages of the book also seem to have faded; the protected portion is a purplish brown, but the rest is a dull pinkish brown.
The surface is largely intact, showing only a few scattered pinpoint losses and scratches. There is an extensive network of branched age cracks throughout the paint layers. The cracking and cupping are most severe in areas of green paint and much less so in the flesh tones and areas of red paint. The areas directly over the strainer members are the least cracked. Areas of cupping and cleavage were infused locally with wax resin.
The surface coating is quite discolored, and a strong greenish-yellow fluorescence evident under ultraviolet light suggests that the coating consists of a natural resin. Microscopic examination of the paint surface shows dark resinous clusters that seem to be pushing to the surface from within the paint itself; under normal viewing, they look like small dark spots.
Frame Notes
The frame consists of a carved and gilded Scots pine molding.2 The underlying bole layer is yellow. The frame profile consists of a shallow, carved floral motif on the inner edge, followed by a cove, a band of raised gadrooning, a wide cove, a band of leaf-and-flower ornament, and then two narrow coves. The carved gadrooning has leaves at the centers and corners; it changes directions at the center point of each side. Each corner of the gadrooning and the band of leaf-and-flower ornament have mirrored elements.
Old metal tabs on the back of the frame were once used to hang the portrait.
Notes
1. Wood identification is based on a scientific analysis of the cell structure by dendrologist R. Bruce Hoadley, January 5, 2000.
2. Ibid. |