Book illustration Internet - Original source ill-defined I'm indebted to Race Gentry for bringing this to my alltention (Facebook, The Photographer's Studio: Backdrops and Props, comment, 1 May 2018)
1909, Complete Self-Instructing Library of Practical Photography, volume VII, (Scranton, Pa.: The American School of Art and Photography), p. 60 "Skylight Room Equipment"
