Silver print from a silver gelatin glass negative, 12.5 x 16 cm.
BnF, Prints and Photographs Department, EO-15 (1)-FOL
© Bibliothèque nationale de France
Before the advent of artificial light and more sensitive processes, natural light was indispensable for taking and developing photographs. On the upper floors, huge windows guaranteed the best possible luminosity. The photographers could create a range of variations and effects thanks to filtering blinds, and with reflectors and screens.