A theory about Sargent’s methods-from Stapleton Kearn’s blog

http://stapletonkearns.blogspot.com.au/search?q=Sargent   i haven’t read this yet myself, but it looks interesting.

Studio lighting suggestions from Juliet Aristides

http://www.aristidesatelier.com/blog/studio-lighting   image above form original article by J.Aristides