The Official Website of Lynn Picknett and Clive Prince

The art world is effervescent with excitement at the unveiling of the 'lost' Leonardo, The Saviour of the World (Salvator Mundi) at London's National Gallery. This is the first Leonardo da Vinci work discovered (or rediscovered) for a century. And Leonardo is always big news - quite rightly - but not always for entirely the right reasons…

Briefly, once some horrible overpainting had been removed from what had been considered a poor copy of Leonardo's painting - the latter having disappeared in the mid-seventeenth century - the true quality of the work underneath could finally be appreciated. Experts who have examined it agree it is the long-lost original.

Readers of our Turin Shroud: How Leonardo da Vinci Fooled History will know that in the 2006 revised edition, we featured the painting as new evidence that the artist was the hoaxer behind the Shroud, the hitherto missing physical link between him and the relic. We found a match between the features and proportions of a version of the Salvator Mundi and the face of the man on the Shroud that goes way beyond coincidence (especially given all the other circumstantial evidence of Leonardo's involvement we also presented in the book).

For the comparisons we used what was then considered the best candidate for his original painting, a version in the collection of the Marquis de Ganay in Paris. In the 1970s and 80s the case for this being the original, rather than one of the legion of copies, was made by Joanna Snow-Smith of the University of Washington. Of course, we now know she was wrong, and one that she dismissed as a copy (reasonably given the evidence then available and the dire overpainting) has now been elevated to the status of the real thing.

As we pointed out, even if the Ganay Salvator isn't the original then it must be a faithful copy from the brush of one of Leonardo's top pupils - probably Giovanni Antonio Boltraffio, his most trusted and skilled assistant - and therefore in any case it would reproduce the all-important dimensions of his Master's version. As the Salvator Mundi enjoyed astonishing popularity during his lifetime copies began to be made even before he had finished it. In fact, there are about 20 first- or second-generation copies.

Given that we were so enthusiastic about the connection between the Shroud and the Ganay version, readers may wonder - as we did - how the discovery of the 'new' version affects our case. After all, the big question is: does the 'new official' Salvator Mundi match the face of Shroudman with the same precision?

Yes, it does.

Although at first glance the faces on the two versions of the painting seem more dissimilar - their expressions are very different - as you can see from the comparison on the left, the features do match precisely. Therefore, if nothing else, 'today's' version is a faithful copy. The major exception is the hairline - the hair on the copy is much thicker - but we will discuss that shortly.

Turning to the original, we used the same technique as with the Ganay copy, ensuring the two images of Shroudman and the Salvator Mundi were the same scale and then overlaying the face of Shroudman on that of Christ in the painting. Then we gradually increased and decreased the transparency so that the face of the painting showed through. You can see instantly and dramatically just how remarkably the features match up.

A short film made by Summersdale Productions - click here to watch - shows the results.

As you can see the key features such as the mouth, nose and arch of the brows line up exactly. (Except that because the eyes are closed in the Shroud image there would be a very minor discrepancy compared with the open eyes of the painting.) Perhaps the most impressive aspect is the match between the hairlines of the two images, which actually fit better than the Ganay copy. As we point out in our book, the hairline of the Shroud image is unnatural, basically being forced on Leonardo by the image-making process.

Our case is also backed up by two other items of information that emerged from the rediscovery of the original Salvator Mundi.

Based on the painting technique, Snow-Smith dated the Ganay Salvator Mundi to the later period of Leonardo's life, in the early 1510s when he was in Florence and France. As we believe he faked the Shroud in Milan in the early 1490s - his version of the 'relic' replacing an earlier, cruder fake, was first displayed near Milan in 1494 - he would have had to return to the Shroud to paint the Salvator. However, although opinions are divided among the experts who have examined the 'new' version, most place it earlier in his career, during his time as court painter in Milan in the 1490s. That is, around the time we believe he made the Shroud. The evidence is mounting.

Secondly, an aspect of Leonardo's interpretation of his commission that we had overlooked was prompted by Hasan Niyazi's discussion of the painting's iconography on his Three Pipe Problem art history web site. The Salvator Mundi was an established example of Catholic iconography long before Leonardo was commissioned to paint his version, and followed a standard format - Christ shown full-face, raising his right hand in blessing and holding a solid orb (often surmounted by a cross) in his left. But Leonardo has made the orb a clear crystal sphere. As Niyazi points out, 'Observers have linked the appearance of this feature in Salvator Mundi as a demonstration of Leonardo's fascination with optics…'.

We would certainly agree with that - except it doesn't go nearly far enough.

We concluded that Leonardo used an early photographic technique to create the 'miraculous' image on the Shroud, employing a camera obscura to project the image onto cloth that had been impregnated with light-sensitive chemicals. We were the first people to publish the results of hands-on experiments in 'Shroud'-making, showing it was possible to create such an image using materials and technology available in Leonardo's day. Coincidentally, more or less at the same time, South Africa's Professor Nicholas Allen also used a camera obscura to demonstrate how the Shroud image was created. A major difference between our experiments was that we used glass lenses whereas, as Allen pointed out to us, lenses ground from quartz crystal (which he used) were more likely to have been used in the Renaissance. (Predictably, lens grinding was yet another area of Leonardo's expertise.)

Could it be that the crystal sphere in Christ's hand in the Salvator Mundi is a cheeky hint of a further connection between the painting and the Shroud - yet another clue left by Leonardo for posterity?

The match between the Shroud and this major work can be explained in one of two ways. The first is that Leonardo copied his painting directly from the Shroud, obviously proving he had access to it. The second is that he based the Salvator on himself, in which case it supports our contention that Leonardo also used himself as the model for the man on the Shroud.

Either way it's a direct connection between Leonardo da Vinci and the Shroud of Turin.

This is highly significant. Our critics have always objected that - despite the welter of circumstantial evidence we had accumulated to link the two - there was no hard or documentary evidence. Nothing tangible. At the time they were right. The absence of such evidence was in fact rather predictable since Leonardo's involvement in faking what was intended to be the greatest (and most lucrative) relic in Christendom would have obviously been Beyond Top Secret. But we've always felt a little uncomfortable arguing from absence of evidence. And it doesn't fit Leonardo's character - the ultimate psychological game-player. Surely he of all men would have left some clue for posterity...

And that's precisely what he did in the Salvator Mundi.

This new revelation doesn't, of course, prove that Leonardo actually made the Shroud. But then again, if he had such intimate knowledge of the 'holy relic' you'd think he would have boasted about it, or splashed the fact as PR for the Church. But no. We had to piece the story together, after 500 years, so clearly there was something about the whole business he desperately wanted to keep secret. And the atmosphere of secrecy fits with our scenario that he was part of a Vatican plot to foist the ultimate fake relic on an unsuspecting and devout flock who would pay anything to see it.

But being Leonardo, he couldn't resist leaving clues - and being us, we couldn't resist following them up.