The paintings have been surface-cleaned, areas of unstable paint have been consolidated, and discoloured varnish has been removed. Where necessary, a new varnish has been applied as a final step. The frames have also been cleaned and restored.

On the paintings People on the Rooftops in Valencia and Shoemakers’ Stall in a Square in Valencia, the conservators discovered the original wax varnish. Written sources indicate that between 1911 and 1913 Willumsen finished some of his paintings with a layer of beeswax, and laboratory analyses have confirmed this practice. In these cases, the conservators chose only to clean the surface and secure areas of flaking paint. The original wax varnish has therefore been preserved in order to maintain the appearance created by the artist himself.

On the painting Michelle Bourret Dancing Harlequin, the old varnish had yellowed over time. This altered the perception of Willumsen’s colours and obscured the subtleties of the work. The conservators removed the degraded varnish and replaced it with a new one, allowing the painting’s colours to be experienced once again as closely as possible to their original appearance.