Martin Luther, bust-length, facing right

optical assessment and radial/tangential section examined employing transmitted light microscopy

[Christoph Schmidt, Gemäldegalerie Berlin; Feb. 2015]

Pigment identification with XRF and optical spectroscopy [see pdf]

At all the points measured lead was detected (probably a lead based pigment in the ground or the imprimatura).

Blue: 1 (background): copper based pigment (probably azurite), lead white

Red: 6 (flesh paint of the hand): some vermilion, lead white; 5 (lips): probably retouching (large quantity of zinc and chrome)

Brown: 4 (hair): probably ochre, lead white, some vermilion, some copper based pigment, large quantity of zinc (siccative?)

Black: 2 (signature): probably carbon black; 3 (coat):probably carbon black, some copper based pigment, large quantity of zinc (siccative?)

[Jens Bartoll/SPSG Berlin, Feb. 2015]

Beech

horizontal grain; panel thinned; consists of three horizontally aligned planks; tangential cut; trimmed at the top and bottom

Dimensions (from the top to the bottom):

1 – l.: 23.8 cm; r..: 24 cm

2 – l.: 6.8 cm; r.: 6.8 cm

3 – l.: 20.7 cm; r.: 20.3 cm

Pale white ground. At the edges the wood was left exposed, occasionally the ground extends over the edge. There is no barbe. The top and bottom edges have been trimmed. Two parallel lines were incised into the ground as guidelines for the inscription a the top edge.

Lead was detected over the entire area of the painting employing X-ray fluorescence analysis (XFA) and may indicate the presence of a lead white imprimatura. another imprimatura is not visible.

Two parallel incised lines serve as guidelines for the inscription. No underdrawing is visible employing infrared reflectography.

PIGMENTS: ( X-ray fluorescence analysis (XFA) and optical spectroscopy)

At all the points measured lead was detected (probably a lead based pigment in the ground or the imprimatura).

Blue: 1 (background): copper based pigment (probably azurite), lead white

Red: 6 (flesh paint of the hand): some vermilion, lead white; 5 (lips): probably retouching (large quantity of zinc and chrome)

Brown: 4 (hair): probably ochre, lead white, some vermilion, some copper based pigment, large quantity of zinc (siccative?)

Black: 2 (signature): probably carbon black; 3 (coat):probably carbon black, some copper based pigment, large quantity of zinc (siccative?)

The damaged condition of the painting makes it difficult to decipher the order of paint application. First the base tone was laid in and worked up to different degrees. The background was painted around the hair, the cloak, the hat and the right side of the face and there is only an occasional overlap. This is clearly visible in raking light. As far as it is possible to tell from the present condition areas were subsequently textured and modulated, shadows and highlights were added as well as details like hair and fur that overlap painted zones. In comparison with other areas of the painting the background exhibits a very varied density, a rapid paint application and a thick impasto in some sections. The brushstrokes are readily visible.

not the original frame

Profiled battens, dark finish

70 cm x 54 cm x 8.5 cm (glazed)

Support:

The painting is cradled and slightly warped. The greatest distance between the contact surface and the reverse of the panel is 3.2 cm. The support is damaged at the bottom left corner and here the paint layers are also affected. In the x-radiograph a metal pin is visible and it probably served to reinforce this area. The support was thinned and cradled. Examination of the edge of the reverse and a cross-section suggests that the support was laminated onto a wooden board. At the centre of the panel the original beech wood support is visible between the battens of the cradle, but around the edge oak inserts were attached. If the panel was not laminated to treat woodworm damage it may be assumed that a rebate on the reverse of the panel was made flush with the thinned panel using the oak blocks. Open worm channels have been filled. One of the corners (left as viewed from the front) is damaged. There are small losses along the edges and isolated horizontal splits in the original panel caused by the cradle (2x at the left edge: each 12 and 4 cm in length).

Paint layers:

The paint layers are in very bad condition and exhibit extensive tiny losses and small scratches. The latter may have been caused by the influence of solvents. The painting is very abraded with the exception of the background. The black cloak, the fur and the hair are extensively overpainted. About 90% of the modelling in the face has been reconstructed (see UV-light photograph). Therefore little can be said about the original paint application. Details like eyelashes, outlines or other textures have to a greater extent been replaced. The depiction is stiff and appears linear. A network of irregular cracks is evenly spread over the entire surface, which also exhibit very fine horizontal micro-cracks. In isolated areas, particularly at the bottom edge, there is distinctive cupping in the paint layers that runs in a horizontal direction. The craquelé is more evident in the face than in the hands. The more extensive craquelé corresponds with the woodworm damage visible in the x-radiograph. There are old surface scratches of varying depths.

Remnants of both an old and newer dark yellowed varnish are visible over the entire surface. In UV-light blue fluorescing area were observed, particularly in the face, which can be identified as retouches and correspond with black areas in the x-radiograph. Under the stereomicroscope a milky coating is visible in these areas that extends over the cracks and covers the retouching. The face and the hands which are better preserved exhibit distinctly different fluorescence. There is a strange contradiction between the apparently perfectly preserved surface of the face and the assumed actual condition. Hardly any original areas can be identified in the face.

1992, 1993: Brief report exists: surface cleaning, removal of old wter soluble retouches; old non-water-soluble discoloured retouches were left; exit holes were filled; retouching and correction with watercolours; application of a final dammar varnish. No documentation available for earlier interventions.