 In 1952, the varnish layer over the background in the painting was evened out.After the second 1956 attack, restorer Jean-Gabriel Goulinat was directed to touch up the damage to "Mona Lisa"s left elbow with watercolour.In 1977, a new insect infestation was discovered in the back of the panel as a result of crosspieces installed to keep the painting from warping.