Joseph Blackburn
Colonel Theodore Atkinson
, 1760

Technical Notes
The support is a plain, slightly open-weave canvas. There are an average of fourteen weft threads per centimeter and twelve warp threads per centimeter. Marked cusping extends from the edges well into the design area. There is a raised area corresponding to a 5 x 2.7-centimeter canvas insert located on the buttons of the coat. The canvas has numerous tears throughout.

The thin, evenly applied ground is light gray and does not hide the canvas texture. Many of the general forms appear to have been first lightly outlined with a thinly applied dark brownish-black paint. Examination with an Ifrared vidicon camera shows what appears to be a small amount of underdrawing for the mouth, nose, eyes, and neck cloth. In general, Blackburn applied the paint in broad opaque and semiopaque layers. The portrait was further developed with glazes and finely painted details applied in a wet-on-dry technique. Paint application was thinnest in the darker areas. Some glazing of dark over light is present in the tablecloth. Low impasto is found in the highlights. The artist reinforced the top contour of the proper right arm with a line of dark paint.

Pentimento is visible in the coat and vest, where the tablecloth was once extended 3.7 centimeters to the right of its present location. The glaze on the tablecloth has faded considerably; areas protected by the frame rabbet show that, originally, the color was a deeper blue. The low impasto has been flattened by past lining treatments. There is overall solvent abrasion, which emphasizes the canvas- weave pattern.

There are some deformations in the paint layer associated with areas of damage. There are small pinpoint losses in the paint layers throughout and also losses associated with tears. Visible staining in the paint layer corresponding to the canvas weave may be the result of past lining treatments.

In 1975 a degraded surface coating was removed, and the painting was revarnished with a brush coat of AW2 (a synthetic resin) varnish and a spray coating of Acryloid B-72.

Frame Notes
The rococo-style gilded softwood frame features pierced carving. The corners are mitered and have cross-spline construction on the back. The inner edge has gadrooning with center points on each side, followed by a sandwork band. The wide outer section features a raised vine-and-floral ornament with large pierce work and has shallow circular punch marks, randomly placed throughout. Tooling marks are clearly visible on the underside of the frame. The frame is gilded with what appears to be a combination of oil gilding and water gilding over a yellow bole.