Gallery reveals master plans

Before and after: Raphael's Madonna

By Ian Youngs BBC News Online Entertainment staff

For the last 10 years, the National Gallery in London has been doing painstaking detective work to uncover the methods of some of the finest painters in history.

Now, art lovers can see the results in the Underdrawings exhibition.

When National Gallery scientist Rachel Billinge trained her infra-red camera on Raphael's 1510 masterpiece The Madonna and Child with the Infant Baptist, she saw something no one had seen since the artist himself.

She saw Raphael's "underdrawing" - his plan for the painting that guided his brush and was covered up by the paint.

	:	In Pictures
National Gallery Underdrawings

The underdrawing is a "stunning" work of art in its own right, Ms Billings says, and is among 19 such preparatory plans put on display alongside the great works they went on to become.

Crivelli's The Dead Christ Supported By Two Angels

Before and after works by Breugel, Cranach the Elder and Altdorfer are among the others on show.

The gallery has uncovered the underdrawings using a 15-year-old infra-red camera, but computer technology has meant they can now be displayed alongside the originals.

It was always known that artists made sketches or set out the shapes in charcoal before starting with the paint, but it was not known exactly how the painters planned each work.

And the scientists got a few surprises when they looked beneath the oil and tempera on the canvases, Ms Billings told BBC News Online.

"Until each one of the paintings was looked at for the first time in our gallery with this technique, we didn't know exactly what we were going to find," she said.

"Each painting is new and exciting.

"We always know roughly what ought to be there, but you never know precisely what you're going to get until you turn the camera on for the first time."

'Extraordinary'

Some of the underdrawings were "enormously free", while others were "incredibly tight and mechanical", she added.

She found "extraordinarily" free loops and whirls found beneath Altdorfer's Christ Taking Leave of his Mother and "vivid delineation" on Saint Gudula's Portrait of a Young Man.

But the biggest surprise came when they pointed the infra-red camera at Pontormo's 1518 work Joseph with Jacob in Egypt.

They saw that the Italian painter had flipped the background design back-to-front after starting work.

Underdrawing of Netherlandish School's The Magdalen

To work out why he changed his mind at a late stage, Ms Billinge produced a diagram to show what the painting would have looked like if she had stuck to his original plan.

"The result was a bit unbalanced - all the important stuff was happening on the left hand side and it was empty on the right," she said.

Although the technique for revealing the sketches was discovered 30 years ago, galleries have had trouble displaying them in the past.

Before they could hook the infra-red camera up to a computer, they had to take scores of photographs of sections of the sketches from TV screens and tape them together.

But computer software developed by the National Gallery digitally pieces hundreds of segments of the sketches together.

And by putting them on display side-by-side with the finished paintings, the gallery is giving art lovers "two for the price of one", Ms Billinge said.

Art in the Making: Underdrawings in Renaissance Paintings runs from 30 October 2002 to 16 February 2003