X-radiography: a long history
With a history going back over a hundred years, X-radiography is one of the oldest technical examination methods for paintings and other cultural objects. X-rays were first discovered in 1895 by the German physicist Wilhelm Conrad Röntgen (1845–1923). The relevance of the new technique to the study of artworks was quickly recognised, and by 1896 the Frankfurt-based professor Walter König (1859-1936) had produced a successful X-radiograph of a painting. Today X-radiography remains a routine and fundamental part of our work in the NGV paintings conservation studio.
X-rays are a form of electromagnetic radiation located on the electromagnetic spectrum beyond visible and ultraviolet light. Because of their high energy and very short wavelength, X-rays can pass through most solid objects. As they pass through paintings, different materials attenuate or block their pathway to varying degrees depending on the chemical composition of the materials and their thickness. This pattern of attenuation and transmission can be captured using a series of individual film plates which are then scanned and digitally assembled using photo-editing software.
While areas of paintings containing high atomic weight elements such as lead attenuate X-rays strongly and therefore appear white, areas composed of carbon and other light elements allow X-rays to pass through, resulting in dark or black areas on the image. Much like medical X-rays, X-rays of paintings show us what is happening beneath the surface, revealing hidden damages and insights into the structure and making process, shedding light on the rich and varied histories of paintings in the NGV Collection.
The North wind (c.1888) is a major large-scale composition by Frederick McCubbin, painted during a pivotal moment in the artist’s early career when he was beginning to explore the fleeting effects of outdoor light and atmosphere and experiment with the direct and expressive brushwork that would come to define his mature Impressionist paintings.
Painted at the time of the centennial of European settlement, The North wind addressed highly topical themes related to Australian identity and the pioneering ethos. The subject is a settler family travelling across parched bushland on a blisteringly hot and windy midsummer day. The grand scale of the canvas, referencing the history painting tradition, elevates this commonplace and familiar narrative to heroic proportions.
The X-radiograph of the painting suggests that McCubbin grappled with this highly ambitious painting for an extended time period, making a series of major revisions to the composition that radically altered the narrative content. By closely comparing the image of the painting with the X-radiograph, we could identify remarkable differences between the underlying image and the image we see today.
Significantly, the X-radiograph reveals a form describing a hillside to the right side of the composition which was later painted out with sky. By removing a microscopic cross-section of paint from this area, we discovered that the hillside was green in colour, suggesting that the landscape was originally lusher and more verdant. It is speculated that the drastic revision of the subject and mood was a response to the severe drought of 1888-1889, which highlighted the plight of the early settlers impacted by Australia’s volatile and often extreme weather.
Consistent with the revised narrative, McCubbin made several other changes that can be seen in the X-ray. A second horse was originally present at the far left but was later painted out, presumably to emphasise the isolation and poverty of the struggling family. The head of the main horse, which was originally painted in a more raised and alert position, was also lowered and the distance between the two hind legs increased, accentuating the sense of fatigue and faltering in the extreme heat. We can render these adjustments more visible by creating a semi-transparent digital overlay of the painting and X-radiograph.
Another intriguing feature of the X-ray is the form reminiscent of a bushman’s hat that appears immediately above the head of the female figure on the cart. This raises the startling possibility that the figure on the cart might have originally been a male figure. The rejection of this earlier figure in favour of a mother and child would have greatly enhanced the pathos of the scene. For contemporary viewers with direct experience of the drought, The North wind would have been an emotionally charged and evocative image, and its atmosphere and mood continue to resonate with viewers over a hundred years later.
John Longstaff’s Gippsland, Sunday night, February 20th,1898
John Longstaff, a former student of the National Gallery School, Melbourne, and winner of the school’s first travelling scholarship, forged an influential artistic career in Europe before returning to Australia in 1895. Gippsland Sunday Night, February 20th,1898, was painted three years later, and was acquired by the NGV soon after painting. It portrays a subject that would have resonated strongly with contemporary audiences; a forest fire incident as part of the disastrous bushfires that devastated Gippsland in the summer of 1897-1898.
After hearing of the Gippsland bushfires, Longstaff was inspired to travel to Warrigal to assist the firefighters. Gippsland Sunday Night, February 20th,1898 was reputedly painted entirely from his memory of the chaos and trauma that he witnessed first-hand.i When first exhibited at the Old Courthouse buildings on Swanston Street in 1898, the dramatic large-scale painting captivated the local media. A review in The Australasian summarised the action taking place:
An excited horseman has reined up, bringing tidings that all chance of saving the homestead has gone. A little further to the right, the settlers’ womankind – a pathetic group – in attitudes that tell of despair and fear, have turned to hear the awful news. The canvas is a highly dramatic and imposing one, the scheme of colour sympathetic, and the handling powerful.i
From the X-ray we can see that Longstaff developed and adjusted the composition in the process of painting, adding and subtracting elements to achieve maximum dramatic and emotional impact. If you compare the image of the painting to the X-ray, you might notice additional figures that do not appear in the final composition. We identified two figures immediately to the right of the central horsemen, and a standing figure at the far right. These were later painted out and replaced with a more dynamic figure hauling a branch and a huddle of terrified women and children.
The two identical-looking trees in the upper left are another striking feature of the X-ray. These are not in fact two separate trees, but iterations of the same tree, which was shifted slightly to the right. If you look closely at the details of the landscape, you may notice other subtle changes. While a log and stump were painted out at the far right, a new larger tree stump was added, possibly to help direct the viewer’s eye up the pathway toward the focal point of the central horseman.
The X-ray suggests that the trees were originally painted using a lead rich paint and were therefore light-coloured. Most were later suppressed, either through tonal darkening or shrouding with smoke, leaving only the three luminous central trees. This minor but important adjustment helps eliminate distractions at the edge of the frame, increasing the dramatic impact of the poignant figure of the central horseman, spotlighted by the embers as if he has just emerged onto an eerie stage.
Another notable feature of the X-ray is the prominent cracking visible in the upper centre. This corresponds to cracking in the paint layer that occurred during drying of the paint, possibly as a result of incomplete drying between layers or artist reworking. Such accidents of technique or ageing can influence our interpretation of paintings, even if not planned or intended by the artist. In the context of the bushfire narrative, the drying cracks evoke burnt timber, and have come to be accepted, and even valued, as an integral part of the painting’s atmosphere and mood.
Nicolas Régnier was a seventeenth-century French painter whose career was largely spent in northern Italy, mostly in Venice. His painting Hero and Leander describes the moment in Musaeus’ ancient story when the female subject Hero discovers her drowned lover Leander, after he had attempted to reach her from his home in Abydos by swimming the four-kilometre stretch of water known as the Hellespont.
The drama of the subject makes it an eye-catching work in the Gallery’s collection; however, it is a work of great interest to conservation researchers for other reasons. The painting was X-rayed several years ago, and it reveals a whole new story about how it was made.
With paintings, these images provide a lot of information about both the paint layers and the structures that support the painting, such as the wood stretcher that holds the canvas: in the image above you can see the timber parts of the stretcher and even the steel tacks around the edges. However, these structural elements can sometimes obscure the information about the paint layers. When this occurs, we can use imaging software to partially screen them out.
Here we get a better look at the paint layers. You will be able to recognise the form of Leander in the lower half of the painting, who appears much like we see in the final image. But when we look for the form of Hero with her arms outstretched, we have difficulty finding her amongst a jumble of other pale shapes. See if you can make out some other forms that do not appear in the finished picture. Can you see a hand in the lower right quadrant of the painting?
These unexplained shapes and forms reveal that Régnier painted his Hero and Leander over an earlier composition which, for some reason, he was unhappy with and decided to discard. Looking at the painting in this orientation it is difficult to make out exactly what it was. However, if we turn the painting upside down, the image beneath becomes slightly clearer:
Digitally modified X-radiograph of Nicolas Régnier’s Hero and Leander, shown in upside down orientation.
Can you identify a new figure? Amongst the tangle of shapes around Hero’s outstretched arms it is possible to make out the form of a reclining woman gesturing to another figure in the top left of the painting.
It is not uncommon to find modifications by the artist in X-ray images, however these changes usually consist of adjustments rather than wholesale repainting of the composition. It is quite rare to find a largely completed work underneath, and sometimes we find that the artist has recycled an old canvas painted by a different artist. We have no reason to believe the underlying image is not by Régnier, although to date we have not found another example of this figure in his work. There is also uncertainty about what scene he is representing. In seventeenth-century Italy there were themes that artists continually returned to, usually from the ancient world or the Bible, and these sources may yield clues into the likely meaning of the underlying painting.
X-radiography: capturing the creative process
Taking an X-ray of a painting is a remarkable and exciting process, because X-rays have the potential to reveal aspects of the creative process that are hidden from view, and not normally recorded during the making of an artwork. It is especially thrilling to uncover a completely different underlying composition. The recycling or repurposing of a canvas or panel might be motivated by practicality or economic necessity, particularly during times of war when rationing rendered art materials relatively scarce. More commonly, X-rays reveal more subtle compositional changes as the original idea is developed and refined during the process of painting, providing precious insights into the artist’s intention and working method.
At their most compelling X-rays can provide a privileged connection with the artist, hinting at their emotional and technical journey as they grappled with and reconciled inspiration, ambition, failure and technical development. They are a fascinating reminder that painting is rarely a linear or straightforward process involving the direct transfer of sketch to canvas, but is frequently dynamic, and responsive to external stimuli, historical events and lived experience. As these case-studies illustrate, even the most successful and celebrated paintings are invariably the result of much persistence, complex problem-solving and hard work by the artist.
Raye Collins is Conservator of Paintings at NGV
Carl Villis is Senior Conservator of Paintings at NGV
Murdoch, N 1948, Portrait in youth of Sir John Longstaff, Angus and Robertson, Sydney, p.178
‘Longstaff’s pictures,’ The Australasian, Saturday 6th August 1898, p.34, retrieved 8 July 2020 https://trove.nla.gov.au/newspaper/article/138602842