Technique and condition
The painting support is a twill canvas that has been primed with a dark, reddish ground. The ground is only visible in a few areas, for example where the surface paint is especially thin. The palette is subdued and limited but this is certainly exaggerated by layers of discolored and unsaturing varnish. The blue drapery, the lace and the fleshtones are the only clearly legible passages although some rich coloration is discernable, for example, in the dark green of the curtain, in traces of red in the costume and in the remote scenery beyond the window. Removal of the varnish will enhance these colors, reveal details, as well as restore the illusion of depth in the painting. However due to the dark ground and the effects of lining and aging, the tonality of the painting has probably shifted permanently.
Extensive changes in the costume are visible with infrared reflectography. In particular the blue drapery has been largely reworked with a different system of folds. The blue glazes that enhance the shadows are nearly transparent in the infrared region and thus are likely to be prussian blue. Prussian blue began to be used commonly in the 18th Century so this is either an extremely early occurrence of the pigment or an indication that this is a later modification.