Conservator, Jim Coddington: Demoiselles d'Avignon has traveled around a bit, from studio to studio, while in Picasso's possession. There's a certain amount of wear and tear, and just the natural aging process.
The painting was first restored in the late 1940s. The varnish was put on in the 1950s to afford protection from dirt and grime. The reason it needed to be restored now is that the varnish had discolored and was muting the bright, vibrant palette of Picasso and was also diminishing the crispness and vitality of the brush strokes. And also some of the retouching that had happened over the years no longer matched the surrounding original paint. By retouching, I mean areas where original paint has been lost, and a restorer has simply retouched the lost areas. And over time, sometimes, those retouchings do not match any longer, and therefore throw off the balance of the painting as well.