Blue Glass
From George Eastman House : Notes On Photographs
The use of blue glass to glaze studio skylights had little to do with its actinic quality; it was preferred for the comfort of the sitter, particularly when direct sunlight was used to illuminate the subject in the early days of the daguerreotype. Blue glass did not produce shorter exposure times, as many assumed it would.[1]
- ↑ Osterman, Mark. 2007. Blue Glass. In The Focal Encyclopedia of Photography: Digital Imaging, Theory and Applications, History, and Science, ed. Michael R. Peres, 48, Focal Press.