1911 Encyclopædia Britannica/Grisaille
Grisaille, a French term, derived from gris, grey, for painting in monochrome in various shades of grey, particularly used in decoration to represent objects in relief. The frescoes of the roof of the Sistine chapel have portions of the design in grisaille. At Hampton Court the lower part of the decoration of the great staircase by Verrio is in grisaille. The term is also applied to monochrome painting in enamels, and also to stained glass; a fine example of grisaille glass is in the window known as the Five Sisters, at the end of the north transept in York cathedral.