Conservation treatment of Hans Holbein's cartoon consisted of careful elaboration of a map-drawing, application of a lens tissue facing, removal of two layers of canvas backing, spray washing with water and magnesium bicarbonate, application of a final backing composed of three layers of hand made Japanese paper, and mounting on a polystyrene foam core faced on both sides with a resin impregnated wood-free paper. Old retouching were toned down to match the original paper colour.