London, April 6 (IANS) Rare sketches of Michaelangelo, Leonardo da Vinci and Raphael discovered by experts at the British Museum will be put on display here later this month.

The exhibition, 'Fra Angelico to Leonardo: Italian Renaissance Drawings', opens April 22. It will showcase the newly found 'underdrawings', which had been erased by the artists, with new techniques developed for drug detection and forensics.

One of the images reveals that Michaelangelo based his Bruges Madonna sculpture on a male model as women rarely sat as models for artists during that period. The sketch was found beneath a later drawing for the sculpture, but the earlier work was invisible to the naked eye, telegraph.co.uk reported.

Renaissance artists often reused the same piece of paper for sketches, because the material was so expensive in the 1500s. They would rub out their drawings with stale bread, an early form of eraser.

The drawings was detected with the help of infrared imaging which reveals traces of residual carbon left by charcoal and black chalk.

The Michaelangelo sketch is one of eight previously unknown works discovered using the technique, which has been used for painting before but never for sketches.