Present were the Giorgione scholars, or lovers of difficulty, as we were called, having chosen such a nexus of problems. Complexity and contrary views did not detract from the exhibition, but made it the stronger. Attendance figures showed that it had been very popular with the Viennese public. The show had been marketed in Venice, in a mood of flamboyant positivism, as Giorgione and the Wonders of Art; and in Vienna as Giorgione, Myth and Enigma, emphasising doubt and contradiction. Nevertheless, two large-scale scientific images – infrared reflectograms – neither mentioned nor discussed in the scholarly catalogues, will advance the discipline. They show how Giorgione constructed the compositions of the Tempesta and the Three Philosophers in a way never seen before – of which more later.

The juxtaposition of one work of art with another, however well known they may be as individual pictures, has always the excitement of a cocktail, when at least two different strong spirits react against one another and effect a new outcome in a person’s consciousness. Historians unless they are trained in art-historical skills, never understand the visual, but scientists, who do understand, value visual evidence, because it creates the new. British historians, on the whole, are notorious because they will only privilege the written document, whereas a molecular biologist would privilege the visual notation of genetic codes, and derive new conclusions from an analysis. Among histories, what makes art history unique is the balancing act between the interpretation of visual and written evidence, which can be the experience or a good exhibition. At the colloquium, some scholars were in a negative frame of mind. and attacked the sources. Vasari bashing was the flavour of the morning, with one art historian claiming that not a single birth date given in Vasari’s Lives of the Artists was correct. But how can one tell if, as in the case of Giovanni Bellini, Giorgione and Titian, no baptismal act survives?

The museum in which the exhibition was located has a collection that was formed by the mid-seventeenth century and that, give or take a few bequests or acquisitions, has remained virtually the same ever since. A few loans from Venice, and some from other museums, together with significant works from their own collection, sufficed to create this excitement.

The Vienna exhibition was completely different to the sister version. Several significant loans had come to Vienna from Giorgione’s birthplace, principally the Tempesta, which looked surprisingly different in another museum, and seemed to yield further secrets under a more revealing system of lighting. The curator, Sylvia Ferino, had the brilliant idea of covering the paintings with non-reflecting glass, so that the lenders would permit the public to come closer to the pictorial surfaces. Usually, the public is caged back from the imagery, and only allowed to sigh at a distance. The looking experience was more engaging than the usual context of a museum hang. It was much more like seeing a painting in conservation. Up close and personal, the Tempesta yielded further secrets: perhaps the most significant of all was the presence of a woman on the bridge carrying something on her head, previously unnoticed in the vast literature on the painting. The woman on the bridge was clearly shown in a new infrared image of the painting, which had been taken after the Venice show, using a new machine developed by the Physics Department of Milan University. On the surface of the painting, the woman’s body was visible, but only the trace of her head, so abraded was the painting in that area.

Between Venice and Vienna, as mentioned earlier, two paintings had been subject to scientific analysis: the Tempesta and the Three Philosophers. The infrared imagery of the underdrawing was displayed by digital means on huge screens, the same size as the paintings themselves. They looked as though they were the original infrared screens themselves, but this was a fiction. In the case of the Tempesta, the image was a composite of an X-ray and an infrared. Purists refuse, probably wisely, to display scientific evidence next to the work itself in an exhibition context. So these large displays, flickering as if they were works of art themselves, were shown behind the originals. The public was intrigued and walked back and forth, understanding, questioning and discussing. I watched them interrogate the new scientific imagery. In Vienna, the public was not underestimated; they were ready for a new museum experience. If only Australian museum directors would take their publics more seriously.

On the day after the exhibition ended, a few of us were invited to stay for a magical morning of discussion, before the exhibition was dismantled. Once again, the presence of the paintings enchanted us. Giorgione’s portrait of an old woman, known as the Col Tempo, described in every inventory as a portrait of his mother, is still in her original frame. Years ago, I published an inventory of the collection in which she originally hung, which showed the frame was original and that the old woman, as once shielded by a painted cover. We tried to see how the frame would have worked with a movable surface, and were defeated. Renaissance collectors covered their pictures with paintings that protected the interior, and made a viewing experience like the act of opening a treasure box.