Identification of pigments
Samples of paint were made into cross sections and dispersions. These were examined under magnifications of up to 400 times with reflected and polarising light microscopy.
Blue skirt near the juncture with the breastplate
Detail of the blue skirt at the juncture with the breastplate
and a magnified cross section of blue pigment
The blue pigment was confirmed as good quality, coarsely ground azurite mixed with lead white and some yellow ochre. Beneath this is the thick yellow glaze over a very thin layer of silver leaf and a dull orange bole. A thin, uneven black layer beneath may correspond to underdrawing. A fragment of translucent gesso is also present.
Green feathers at the juncture with the red cloak, right hand side
Detail of a green feather and the red cloak in the painting
and a magnified cross section of pigments
The green layer is slightly translucent with a proportion of lead white present. Although this pigment was not analysed, both malachite and green earth were identified in other green samples from the painting. It lies over the bright orange-red, presumably vermilion, of the cloak. The upper glaze of the cloak is not present in this sample indicating the cloak was just blocked in when the wings were painted.
Red cloak at the collar bone, right hand side
Detail of the red paint on the cloak and a magnified cross section of the red pigment
The same orange-red layer appears, as described in the previous sample. On top of this is a semi-translucent glaze containing many crystalline red particles. This layer is visible in cleaning test areas and is one of the relatively well-preserved layers of the original painting. An orange-brown glaze lies beneath the red paint and a very thin layer of silver leaf is present at the very bottom of the sample.
Green wing feathers, left hand side
Detail of the green wing feathers and a magnified cross section of the green pigment
The upper layer is a finely ground green overpaint. Beneath this, the original green is a translucent blueish-green. Both malachite and green earth were identified in this layer, along with lead white, yellow ochre, a bone black and an unidentified blue. A number of black particles between the green and the gesso ground may relate to underdrawing in this area.