In 1950, US artist Jackson Pollock dripped black paint onto a 12-square-meter (129-square-foot) canvas he had spread out on the floor. The work, called "Number 32," is now considered one of the most radical paintings of Abstract Expressionism.

Now owned by the art museum Kunstsammlung Nordrhein-Westfalen in Dusseldorf, the painting is undergoing its first cleaning in 65 years.

The museum's director of restoration, Otto Hubacek, discussed with international colleagues different ways to whiten the now gray-yellowish canvas, but finally decided to develop his own method, which he plans to present soon at the Metropolitan Museum of Modern Art in New York, according to German news agency dpa.

Inspired by restoration done on paper works, Hubacek built a device which blasts wheat starch on the canvas. The starch is then carefully cleaned with a miniature brush set on a vacuum cleaner. The black paint on the canvas is to be avoided during this cleaning process, as the starch could affect it.

This painstaking process will require between 200 and 300 hours of restoration work, which Hubacek wants to undertake himself, comparing his detailed approach to "handwriting."

Through his exploration of the painting, Hubacek has discovered traces of footprints and coffee stains. These will stay on the painting, he says, as "The coffee stains belong to the work."

eg/kbm (dpa, kunstsammlung.de)