Ashok Roy is director of collections, Jill Dunkerton is senior restorer in the conservation department, andMarika Spring is head of science, all at the National Gallery, London. Helen Howard, Gabriella Macaro, Rachel Morrison, David Peggie andNelly von Aderkas are members of the scientific department, and Rachel Billinge is a member of the conservation department, all at the National Gallery, London.Jacqueline Ridge is keeper of conservation and Lesley Stevenson is senior paintings conservator, both at National Galleries of Scotland.