The acclaimed National Gallery Technical Bulletin features contributions by curators, scientists, and conservators, on materials and techniques of painting, and the scientific examination of paintings. Volume 33 presents new findings on the use of colorless powdered glass in 15th- and 16th-century European paintings; the conservation and restoration of Niccolo di Pietro Gerini's Baptism Altarpiece; an examination of Renoir's The Umbrellas; the techniques of Adolphe Monticelli; and a comprehensive study of Vuillard's La Terrasse a Vasouy.