Martin Kemp sifts the evidence that Leonardo da Vinci painted the newly emerged work Salvator Mundi.
Leonardo da Vinci: Painter at the Court of Milan
National Gallery, London. Until 5 February 2012.
New paintings by Leonardo da Vinci do not come along every week, although the volume of messages in my inbox from owners of putative Leonardos might suggest to the contrary. The last painting that gained general acceptance as a Leonardo is the Benois Madonna (Madonna with a Flower), which made its public debut in 1909.
Now we have the newly emerged Salvator Mundi (1502–08) — Christ depicted as saviour of the world. It is a highly traditional subject that even Leonardo had to lay out in a conventional manner. A fully frontal Christ, who looks unrelentingly at us, blesses with one hand and holds an orb in the other. The painting made its public debut on 9 November at the National Gallery in London, as part of the exhibition Leonardo da Vinci: Painter at the Court of Milan — the greatest gathering of Leonardo's paintings ever organized.
There are numerous copies and versions of Salvator Mundi, as there were of many of Leonardo's small-scale paintings. How do we know if one of them is actually by Leonardo? There are two main resources that can be used: traditional art-historical arguments and newer techniques of scientific examination.
The standard art-historical arguments centre around connoisseurship — the validation of the attribution by an expert's eye. Although connoisseurship still has a role to play, and many experts depend on it, it involves subjective criteria that should long have been superseded as the key tool of attribution.
Other art-historical evidence can help. Two drawings by Leonardo in the Royal Collection at Windsor, UK, show the draperies of Christ. There is also a record that Leonardo's pupil, Gian Giacomo Caprotti (called Salaì), owned a “Christ in the Manner of God the Father”. Salaì, to judge from documents of 1525 that record his property after his death, had managed to lay his hands on a central stock of Leonardo paintings, including the Mona Lisa. What happened to Salvator Mundi after that is unclear, although it did appear, in the seventeenth century, in records of the English collections of King Charles I, King Charles II and the Duke of Buckingham.
We can now supplement the art-historical arguments with the scientific. The evidence is of two kinds.
The first involves the technical examination of the painting, as undertaken during its recent conservation. It revealed that once, Christ's thumb was more upright, suggesting that this painting is not a straight copy. More importantly, examination by infrared reflectography, which involves bouncing infrared light off the white priming of the panel, has revealed characteristic signs of Leonardo's idiosyncratic technique. Particularly significant are clear signs of the painter pressing the edge of the palm of his hand into the wet paint, as can be seen above Christ's left eye. This was one of the techniques Leonardo used to create the soft, elusive effects for which he was renowned.
The second variety of 'scientific' evidence is particular to Leonardo. He insisted that painting is a science — it relies on a systematic body of knowledge based on a deep scrutiny of cause and effect in nature. He saw painting as “the sole imitator of all the manifest works of nature ... which with philosophical and subtle speculation considers all manner of forms ... all of which are enveloped in light and shade”. For any painting to be recognized as a Leonardo, it has to bear witness to such mighty ambitions. The Salvator Mundi does on two main optical counts.
Leonardo was always interested in the functioning of sight, and in a manuscript largely devoted to the optics of the eye, written around 1507, he turned his attention to the issue of focus — what a photographer would call depth of field. He realized that something too close to the eye is not seen clearly, although he did not have any conception that this resulted from the focal range of the lens. He also stressed the loss of clarity when something became more distant. As he argued that images were received in the eye across a receptive surface, not at a single point, he maintained that the eye does not perfectly “know the edge of any body”.
In Salvator Mundi he plays with these depth-of-field problems. None of the contours is absolutely sharp, but the blessing hand and the tips of the fingers cradling the orb are discernibly clearer that the features of Christ's face. The rapid loss of clarity in depth serves to give space to what would otherwise be quite a flat image.
The other optical effect is unique to this painting, both in Leonardo's work and in the Renaissance more generally. The orb is not the standard globe of the world. It is translucent and glistens internally with little points of light. These are not the spherical bubbles found in glass, but are the kind of cavity inclusions (small gaps) that appear in some specimens of rock crystal and calcite. Leonardo, we know, was considered an expert in such semi-precious materials. It seems that he observed the double refraction produced by calcite. The heel of Christ's hand exhibits two distinct contours, not in this case due to a change of mind.
The crystal orb is not simply a visual tour de force. It reworks the meaning of the painting. In Ptolemaic cosmology, the stars were embedded in the fixed crystalline sphere of the heavens. The saviour of the world is also the saviour of the cosmos. Leonardo characterized God, who created the whole system, as the 'Prime Mover', who stands outside the sphere of the fixed stars and who set everything in motion at the moment of creation.
Leonardo has taken a stock subject and recast it. The soft, out-of-focus effects for Christ's head, endowing him with an ambiguous expression, invite the viewer to speculate on the supreme mystery of his flesh-and-blood presence on Earth. Leonardo also signals, through the crystalline sphere, that the domain of Christ's Father extends to the whole of the cosmos.
However skilled Leonardo's followers and imitators might have been, none of them reached out into such realms of “philosophical and subtle speculation”. We cannot reasonably doubt that here, we are in the presence of the painter from Vinci.
About this article
Cite this article
Kemp, M. Art history: Sight and salvation. Nature 479, 174–175 (2011). https://doi.org/10.1038/479174a
Leonardo DaVinci’s contributions to medical physics and biomedical engineering: celebrating the life of a ‘Polymath’
Australasian Physical & Engineering Sciences in Medicine (2019)