Scientists digitally reconstruct Renoir portrait

A visualization of the painting in its original appearance (left) and the original Madam Leon Clapisson (1883)

Scientists have made a digital reconstruction of a Renoir portrait with its original colours as they would have looked to the artist when he finished the painting in 1883, before the red pigment he used had faded due to its sensitivity to light.

The original portrait of Madame Leon Clapisson has faded significantly over the past 130 years but the original colour of the reddish background had been preserved under the frame of the painting, said Richard Van Duyne of Northwestern University in Evanston, Ilinois.

Using a technique called ramen spectroscopy, Dr Van Duyne was able to analyse the molecular make-up of the pigments used in the painting and make comparisons between the exposed and unexposed parts of the portrait to make a full-sized digital reconstruction.

The analysis showed that Renoir used a brilliant pigment called carmine lake, which is composed of organic molecules and is extremely sensitive to light. The analysis is one of several on the chemical make-up of artworks, including one showing that Picasso used ordinary house paint in some of his paintings.