Technical analysis of 'Sibylla Palmifera'
This painting was completed over a 5-year period, between 1865-70. When 'Sibylla Palmifera' was examined in the studio earlier this year it was found to be in very good condition. As with 'The Blessed Damozel' there were very few areas of damage or loss. For this reason it was only possible to take a couple of samples from this painting. These were taken from the extreme edges of the paint.
In contrast to the 'Blessed Damozel', the surface of 'Sibylla Palmifera' was much less glossy. There was no evidence of the thick pigmented layer that was seen on the 'Blessed Damozel'.
A sample of red paint from Sibylla's gown at the bottom edge (see image below) showed a deep red colour that has a bright orange-red fluorescence in UV radiation, which is characteristic of a red lake pigment. Analysis by SEM-EDX identified aluminium, probably from an aluminium hydrate used as a base for the translucent lake pigment. The ground was identified as lead white.
Cross section of the red gown from Rossetti's 'Sibylla Palmifera', taken in UV fluorescence, showing the fluorescing red lake pigment. Taken at x 250 magnification.
Both 'The Blessed Damozel' and 'Sibylla Palmifera' were x-rayed during examination.
X-raying is a procedure that has been used in analysis of paintings for many years. It was first used in 1896 and by the 1930s it had become general practice. At the National Conservation Centre, paintings are not routinely x-rayed unless the procedure is hoped to tell us more about the work. X-raying is carried out in-house in a specially designed room. If necessary an x-ray can be exposed and developed within an hour. The paintings are laid flat on a metal framework, with the x-ray source beneath the painting and the sheet of x-ray film laid carefully on top. Often several sheets of film need to be used to complete the full image, 'Sibylla Palmifera' for example needed 9 separate sheets of x-ray film.
The x-ray of 'Sibylla Palmifera' is interesting as it shows areas where the canvas size was expanded with additional pieces of canvas added to the outer edges and areas where the artist reworked parts of the composition.
The above image is a montage of the 'Sibylla Palmifera' x-ray. At first glance an x-ray can be very confusing. It is important to realise that when you view an x-ray you are looking at the whole structure of the painting, the paint layers, ground layer, canvas and stretcher. Therefore in the case of the above x-ray, as well as the paint, you can also see very faintly the stretcher and the panel insets from the blind stretcher.
Image of the reverse of 'Sibylla Palmifera'. Here you can see that the stretcher has panel inserts as used in Dante's Dream.
A close look at the x-ray shows this blind stretcher, or more obviously the nails that hold the wooden panels of the blind stretcher into the stretcher.
This image is top left in the x-ray and shows several different things about the structure of the painting. Firstly the tacks on the outer edge show where the canvas is held onto the stretcher. Secondly the inner tacks show where the panels from the blind stretcher are tacked to the stretcher. There are also staples visible around the outer edge of the painting, and this is where the edge of the canvas is attached to the reverse of the stretcher.
The final thing that this x-ray shows about the structure of the painting is that Rossetti added on strips of canvas around all four edges.
This detail from the top right of the image shows quite clearly the canvas additions around the edge of the painting. The canvas weave is not completely aligned at the butt between the addition and the inner, original canvas. There is no doubt that these additions are original. It was relatively common for Rossetti to send his paintings away to be enlarged after starting to paint them. Perhaps this is one of the reasons why it often took him several years to complete his paintings.
An x-ray can also reveal something about the pigments and the way the paint was applied. What shows up on the x-ray film depends very much on the density of the materials used to construct the painting. Pigments that are made from heavy metals such as lead white are very dense so show up as light areas on the x-ray.
Whilst the face of Sibylla is clear in the x-ray, other areas such as the hands, shown above next to an ordinary detail of the area, are not distinguishable. This can probably be attributed to a number of things. Rossetti added canvas to the painting and in order to disguise this fact he would have painted over the seams. Much of the lower half of the painting is unclear in the x-ray, and has a patchy, irregular look. This irregular layer is very white in places and may consist partly of lead white, applied generally, perhaps with something like a pallette knife or wide brush to prepare the canvas to paint on. This is mostly concentrated to the area of original canvas. This may suggest that when Rossetti had the canvas extended, he rubbed down the original paint in the lower half, prepared the canvas with a rough ground layer and then repainted this section.