JOHANNES VERMEER's visitor, Pieter Teding van Berckhout, recorded in 1669 his wonder and intense curiosity at the Dutchman's use of perspective. It gave the pictures what would later be described as their photographic quality, a quality that marked one of the milestones in the history of art.
That curiosity consumed Jorgen Wadum as he leaned over the Dublin Vermeer, more than three centuries later, on a table in an Antwerp warehouse. It was 1993. He had joined Andrew O'Connor from Ireland's National Gallery in Antwerp to fetch the painting recovered by the Belgian police in an elaborate sting that had netted most of the stolen Beit collection.
Now owned by the gallery, it is one of the finest of Vermeer's works. In Lady Writing a Letter will her Maid a young woman devotes her rapt attention to a (love?) letter while her maid casts a patient, laconic gaze out the window.
And then Wadum saw it a tiny pinprick in the left eye of the mistress. It was enough to cast in an entirely new light the conventional wisdom on Vermeer's technique, specifically his creation of perspective.
Wadum, the Danish chief restorer at the Mauritshuis gallery in The Hague, had already started preparation for the exhibition that is now the talk of Europe, the first assembly of the body of Vermeer's work since a sale (300 years ago to the month) of the collection of one of his early admirers. Twenty two pictures of the still extant 35 have been brought here to the Hague from all over the world.
It has been seen by 350,000 in Washington and will have been seen by some 400,000 in The Hague when it closes in June. Already every advance ticket has been sold and crowds queue every day from 7.30 for the 200 daily tickets that are left.
It had been believed that Vermeer created his perspective by using a projection of his subject matter from a machine called a camera obscure in effect, a large scale version of a camera which projected on to a white surface instead of film. Wadum was not convinced. Such a process would have been very cumbersome and much of the work would have had to be done in the dark.
The pinprick solved the mystery.
The use of a single vanishing point on a picture's horizon allows an artist to draw converging orthogonal lines to give a painting's perspective its internal consistency. Vermeer would have held a pin in the vanishing point and, with a thread coated in chalk pulled taut to any point on the canvas, marked out the converging lines.
And Wadum has since shown that 13 paintings still have evidence of the pinprick at the vanishing point, confirming that Vermeer used the technique, which was increasingly common among architectural painters of the time.
Wadum's study of the geometry of the paintings has also helped to provide a remarkably simple confirmation of the chronology of Vermeer's work. Vermeer's earlier pictures, particularly the characteristic tiling on the floors, show evidence of a struggle with the theory of perspective. The tiles appear at the front of the picture to drop away as if the floor is gently sloped.
Gradually in later paintings, by further separating two similar, but external, reference points for perpendiculars, Vermeer succeeds in overcoming this problem and the order in which paintings were produced then becomes deducible by a simple mathematical test.
Vermeer's genius, however, consists in far more than a mastery of technique either in terms of perspective or of a remarkable knowledge and use of light and colour that would be rediscovered two centuries later.
Here is a man very much of his time, who, through the simplest of glances and hints of body language or the juxtaposition of the mundane, can conjure up layer upon layer of psychological and social meaning the wealth and self confidence of the bourgeois, the introspection of the artist's subjects, often preoccupied with books, letters, maps or music, that suggests the age of reason, the shared, knowing glances of complicity and yet innocence I found the humour of his observation enthralling. In a charming joke at the expense of realism a mirror reflects a young woman looking at a man gazing at her, when she is in fact looking ahead. Who is courting whom?
In the fine catalogue Albert Blankeit suggests of Dublin's Mistress Writing that a small tome on the floor in front of the table is a discarded volume of model love letters, much in vogue at the time. So our mistress's concentration on her own original letter is explained, as is the wandering gaze of the maid in for a long wait.
It has also become clearer that the artist was indeed well recognised in his own time, with a ready outlet for his work locally. Many prominent international visitors came to Veneer's studio in Delft.
Dr Wadum is to deliver a talk on Vermeer in Dublin in late August or early September. Don't miss him.