Hidden Rembrandt sketch discovered in 'Operation Night Watch'

Experts have uncovered a previously hidden sketch beneath Rembrandt van Rijn's "The Night Watch," allowing art historians new insights into how the masterpiece was painted, according to Amsterdam's Rijksmuseum.
Museum director Taco Dibbits hailed the discovery as a "breakthrough" on Wednesday, presenting the new research into the 1642 painting.
"We always suspected Rembrandt must have made a sketch on the canvas before embarking on this incredibly complex composition, but we didn't have the evidence," Dibbits said in a statement.
Researchers at the Rijksmuseum have worked for the past two and a half years on "Operation Night Watch," using imaging techniques and computer technology to collect a vast amount of data on the painting.
"This allows us to look over the artist's shoulder, as it were, and watch as he takes the first steps in the making of a masterpiece," the statement said.
Dibbits added: "We are currently able to look beneath the surface of the paint better than ever before. ... We have discovered the genesis of 'The Night Watch.'"
New technologies allowed experts at the renowned Dutch museum to analyse "in minute detail" the materials used by the Dutch Golden Age painter.
The artist applied a brown "quarts" ground and used a beige paint with a high chalk content for his rough sketch, according to the research.
This is the first Rembrandt painting found to have been prepared using this type of paint.