This journal article describes the conservation by the Laboratoire Central des Musées de Belgique, and the history of treatment of van Eyck's polyptych. Mr. Coremans, director of the Laboratoire proposed to impregnate back and front with a wax mixture (unspecified), heated to between 35 and 40 Celsius with infrared lamps, to reduce overall varnish to the thickness of the Hermits panel and to remove old overpaints. A cross-section taken from an area of previous restoration shows varnish layers, overpaint, dirt layers, vermillion base, ground and glue. The original surface glaze is gone. Treatments began in 1550 with cleaning and continued through 1612, 1663, 1825, 1828-29 (restorations were due to a fire in the cathedral), 1893 (panels sawn apart), 1936 and the present treatment, 1950-51.