Technical analysis of 'The Blessed Damozel' and 'Sibylla Palmifera'

The conservation of Rossetti's 'Blessed Damozel' and 'Sibylla Palmifera' gave us the chance to study his technique in these paintings. The study of the materials and methods used by artists is a routine part of the conservation of a painting. It helps us determine the most suitable treatment for a painting, as well as telling us about an artist's technique. As one of the Pre-Raphaelite painters, Rossetti was painting in a particular style that is famous for the brilliance of the colours and the luminosity of the paint.

The letters and diaries of the Pre-Raphaelites have been studied in depth for clues about how they created the distinctive style and glossy finish of their paintings. The most famous and often-quoted passage is from the autobiography of William Holman Hunt, one of the founders of the Pre-Raphaelite Brotherhood. In this, Hunt describes the use of transparent glazes over a wet ground and the addition of the resin copal to the paint medium.

"Select a prepared ground originally for its brightness, and renovate if necessary with fresh white when first it comes into the studio; white to be mixed with a very little amber or copal varnish. Let this last coat become of thoroughly stone-like hardness. Upon this surface complete with exactness the outline of the part in hand."

"On the morning for the painting, with fresh white from which all superfluous oil has been extracted by means of absorbent paper, and to which again a small drop of varnish has been added, spread a further coat very evenly with a palette-knife over the part for the day's work, of such consistency that the drawing should faintly shine through. In some cases the thickened white may be applied to the forms needing brilliancy with a brush, by the aid of rectified spirits."

"Over this wet ground, the colour (transparent and semi-transparent) should be laid with light sable brushes, and the touches must be made so tenderly that the ground below shall not be worked up, yet so far enticed to blend with the superimposed tints as to correct the qualities of thinness and staininess which over a dry ground transparent colours used would inevitably exhibit. Painting of this kind cannot be retouched except with an entire loss of luminosity."

Hunt, WH 1905-1906 'Pre-Raphaelitism and the Pre-Raphaelite Brotherhood'. London: Macmillan & Co Ltd., Vol 1 p276

The technical analysis of these two paintings involved analysing microscopic samples of the paint to identify the pigments and painting medium that Rossetti used. The structure of the paint layers was studied in microscopic cross sections of the paint layers, to find out about Rossetti's technique, his use of glazes and locally applied 'wet' grounds. The pigments were identified using a combination of transmitted light microscopy, which tells us about the optical properties of individual pigment particles, together with elemental analysis of the paint cross sections in the scanning electron microscope (SEM).

All text by Siobhan Watts and Rebecca Kench.