Henry VR (12 May – 9 Sep 2018) is the Art Gallery of New South Wales’ first virtual reality exhibition, focusing on the restoration of a Tudor portrait of Henry VIII in the Gallery’s collection. The VR installation transports viewers into a reconstruction of a 16th century London artists’ workshop, where they can experiment with the materials and pigments used to create the painting, and experience the sights and sounds of Tudor-Era London before teleporting inside a particle accelerator to view the unique X-Ray fluorescence elemental maps produced at the Australian Synchrotron during the restoration process. Henry VR uses virtual reality technologies to complement the mission of the gallery to interpret, present and preserve works of art of cultural value.
In 2014 a portrait of Henry VIII painted on oak panel dated from 1535 to 1540 was examined in the light of recent research undertaken at the National Portrait Gallery (NPG) in London on a group of early Tudor portraits that included four versions of similar composition. All five paintings share compositional features, although none of them is an exact copy of the other with differences in costume details, the position of the fingers and the measurements of each panel.
The Sydney Henry VIII painting had not been on display for many decades due to the poor condition of varnish and restoration paint layers. Initial investigations suggested that a conservation treatment would allow the work to be exhibited without the obscuring and discoloured restorations that had been applied over time.
Little is known about the artisan workshops that may have been involved in the production of these early English portraits. Authorship of the Sydney painting (and the similar works in London) has been, for many decades, attributed to an anonymous Anglo-Flemish workshop. It is not clear whether the five paintings of Henry VIII derive from a single workshop or were produced by a number of different workshops or artists. Little associated documentation on London workshops and artistic practice prior to 1540 has survived and so the paintings themselves are potentially the only source of insight into these questions. Roy Strong, Director of the National Portrait Gallery (1973–1987) writing about these paintings in 1982 suggested that analytical studies and imaging techniques of the paintings have the best potential to provide new insight into authorship and workshop practice.
In order to assess how the Sydney painting might relate to the known group of early Tudor portraits in London, a full technical study was initiated at the Art Gallery of NSW, including infrared studies to look for underdrawing, photography in ultraviolet light to compare fluorescence of varnish and paint layers, dendrochronology of the oak panel for dating, sampling of microscopic paint samples in cross section to examine the layering of the paint and transmission X-radiography to image the elementally heavy pigments such as lead white used in ground preparation layers and white paint. The results of these analytical and imaging techniques were compared with the same techniques on the London paintings.
In addition, the unique capabilities of XRF spectroscopy mapping at the high resolution offered by the synchrotron source and the fast acquisition Maia X-ray detector used at the Australian Synchrotron provided unequalled analytical clarity of the paint layers, not possible with the traditional X ray method. Although a rapidly developing field, only a small number of paintings to date have undergone full synchrotron- sourced mapping since the first major study involving van Gogh’s Patch of grass in 2008.
The application of both novel and established methods of technical examination to these paintings has led to the discovery of a body of new information about artistic practice that would have been unobtainable by any other means, notably to explore the way in which versions and copies were produced – the close examination of art objects is indeed fundamental to research into material culture and art historical practice. The scrutiny of a painting’s surface, its construction and its materials, provides a crucial foundation for any study that seeks to anchor an object in its historical, artistic or iconographic context. In the absence of substantial documentary evidence for the way in which artists painted in the Tudor and Jacobean periods, technical study can provide a wealth of information about how paintings were made and how they have changed with time, and evidence for and an interpretation of how they may have looked when first painted.
In additional to providing detailed information regarding the condition of the painting prior to conservation treatment, forensic analysis was undertaken to establish physical similarities to the other panel paintings of the same subject in London. It was hoped that by studying this group of works that new findings would emerge regarding authorship and the emerging artistic practice of portrait painting in London in the 1530s. Conventional imaging techniques, X-radiography, infrared reflectography and ultraviolet fluorescence undertaken at the Art Gallery of New South Wales suggested damages to the painting. These include a break in the panel through the centre, the addition of an extra panel piece along the right edge and extensive overpaint by previous restorers. Comparative examination of several panel paintings of the same subject from a similar period, (National Portrait Gallery London, and Society of Antiquarians, London) suggest the convention was to include slashed sleeves and a hand on the right side and the shadow of the King’s hat on the wall behind. These elements are no longer visible on the Sydney painting and are not clearly imaged in the X-radiograph and have either been over-painted or lost.
The use of Synchrotron X-ray fluorescence mapping allowed the imaging of the chemical elements used in the pigments of the painting, since each chemical element in the pigments produces a unique fluorescence signal when appropriately illuminated by X-rays. As each pigment colour used by the artist is composed of a set of chemical elements, this gives the potential for the identification of original paint layers as distinct from those added as restorations later.
Under the granting of Australian Synchrotron time to the Art Gallery of New South Wales by the New South Wales Department of Trade and Investment, the portrait of Henry VIII was transported to Clayton in Melbourne in 2013 for analysis on the X-ray fluorescence microscopy (XFM) beamline. The use of Synchrotron X-ray fluorescence mapping is opening up new understanding about paintings and artist’s processes that have never been seen before. A painting by Vincent van Gogh Patch of grass 1887 (Kröller-Müller Museum) imaged in this way at a Synchrotron in Europe revealed an earlier painting dating from 1884-85 on the same canvas of the head of a peasant woman. While the technique offers exciting new possibilities for imaging unseen parts of paintings, limitations of Synchrotron mapping, including with the van Gogh painting, have been the length of time required to acquire detailed maps.
The XFM beamline at the Australian Synchrotron incorporates the Maia X-ray fluorescence detector system, developed in collaboration between the CSIRO and Brookhaven National Laboratory, USA. The Maia detector system enables fluorescence mapping at rates hundreds of times faster than conventional systems. This capability, combined with the tightly focussed X-ray beam from the Synchrotron, allows large objects, such as paintings, to be mapped with pixels of about 100 microns in size, in a relatively short time. The Henry VIII portrait this is particularly useful as the painting is extremely finely rendered, including each hair on the King’s beard as a separate brush stroke in the region of less than one millimetre wide. Australian Synchrotron capabilities in rendering extremely detailed X-ray fluorescence maps are showcased by this example.
The maps of the Henry VIII portrait were acquired at the Australian Synchrotron over three days at two different X-ray energies, one excluding the influence of the element lead, the other highlighting lead as found in the lead white ground layer preparation on the panel and the white elements of the painted layers. The x-ray fluorescence lead map compared with a conventional X-radiography demonstrates the clarity of the new technique in imaging the painting, showing the broad diagonal brush marks with which the white ground layer was applied. It also images for the first time the sleeve at the lower left that appears to be a slashed sleeve with the white shirt undergarment pulled through the decorative cuts in the upper garment. This was obscured on the painting by a broad dark restoration.
Other elemental maps produced by this technique answer further questions regarding the condition of original paint layers hidden by restorations. The X-ray fluorescence map of the element mercury is informative of the flesh and beard as the paint in these areas is based on the pigment vermillion (mercuric sulphide), a rich bright red colour mixed with lead white. What is remarkable about this X-ray fluorescence image is the subtle variations in shades and tone to describe the volume of the face which are a result of varying concentrations of vermillion equating in the painting to different amounts of the red pigment. Likewise, the fine brush strokes defining each hair on the sitter’s face is rendered in this image in detail, no longer visible on the painting itself due to the discoloured varnish layers. The detail of the outer garment of the slashed sleeve cuff at the lower left is made visible, but most remarkable is the clarity of the artist’s change to the position of the little finger on the sitter’s right hand, initially painted folded under, and later straightened in a restoration. Unfortunately no indication of the other hand is visible as would be expected if it was still extant, suggesting that it has been entirely lost by the damage to the right side of the panel.
The X-ray fluorescence map for the element copper also reveals new information regarding the original paint. Identified as a copper-based green pigment in the background of the painting, the difference between the higher concentration of copper pigment in the shadow at the left is seen, compared to the paler green throughout the rest of the background that has been lightened with the addition of lead white. The cushion under the King’s hand was also been originally painted in this same green pigment, as it shows strongly in the X-ray fluorescence map for the element copper. The cushion had been covered by a dark layer of restorer’s over paint and the original green cushion with its subtle description of shape and folds was revealed with recent conservation treatment.
Perhaps however the elemental map that reveals the most unusual information is that for the element gold. Fine sheets of gold leaf have been laid in place by the artist in a technique similar to that used in religious icons and European paintings from the fifteenth century and illuminated manuscripts. The subtleties of the gold leaf, in places crinkled, folded and torn is visualised in detail by this new imaging technique. No other imaging technique to date has the capability to image gold leaf in this way. Gold leaf is too thin to register in conventional X-radiography and is not made visible in other techniques. In this instance we can see the whole of the gold sheets, the cut angular edges later covered by paint.
The use of Synchrotron X-ray fluorescence mapping is an exciting development in the examination of cultural materials enabling new information to be visualised quickly and effectively. Limitations to its use are the need to take the artwork to the Synchrotron and the availability of the instrumentation and beam time. The Australian Synchrotron is located in Melbourne and applications for use are via a merit-based application for funding partners, by special allocations of time to NSW industry clients, or by direct commissioning of Synchrotron time for commercial access.
A ground-breaking study of the wooden panel itself by Matthew Brookhouse dendrochronologist at the Australian National University is a story in its own right. Oak trees, produce annual growth rings comprised of bands of water conducting vessels which are evident as wood grain. The widths of these bands are representative of the rainfall. Throughout Europe, wood chronologies have been painstakingly compiled from oak samples which now cover thousands of years of recent time. By careful measurement of the sequence of ring widths, a piece of oak can potentially be dated by comparison with the chronologies. Unable to achieve enough accuracy from the damaged exposed ends of the panel Matthew has for the first time has been able to date the panel using a synchrotron map which happened to precisely image our wood grain. We were in luck. The most significant match was found to date the last measurable ring to 1480. Adding in the lost sapwood rings (20-40 years) this moves the earliest possible felling date to 1500-1520 and most likely in an area in the south-eastern corner of England around Sussex. Though it is still to be established whether our tree was growing on a ridgeline rather than the valley floor, this remarkable result is almost identical to that for the Henry panel in the Society of Antiquaries, the one which our portrait most closely resembles.
Research team
Dr Andrew Yip Fellow, iCinema Centre for Interactive Cinema Research, UNSW Project Director
Dr Paula Dredge Head, Paintings Conservation Research & scientific investigations
Dr Anne Gerard-Austin Assistant Curator, International Art Curatorial & historical research
Simon Ives Senior Paintings Conservator Research, science & conservation treatment
Tom Langlands Frame maker Reproduction frame maker
Dr Margaret Sawicki Head, Frame Conservation Framer
Nicola Best Immersive systems engineer, iCinema Centre for Interactive Cinema Research, UNSW
Dr Daryl Howard X-Ray Microscopy Beamline Scientist, Australian Synchrotron
Dr Matthew Brookhouse Research Fellow, School of Biology, Dendrochronology, Australian National University