During conservation treatment planning, with temporary lables used to describe the varnishes present. 
(Fig. 9, John Singer Sargent's later portraits The Artist's technique and materials; Jacqueline Ridge and Joyce Townsend; Apollo Vol. 148, Issue 439 (1998) pp. 23-30)

(Editor's note -- The image here is very poor and hoping someone can send me a better one)

Almina, Daughter of Asher Wertheimer
1908
 

Notes: