Pringle, Andrew · New York : Scovill & Adams Company of New York · leaf 63
ty minutes may be required for development, and the dish must be occasionally moved ; if the exposure has been right the result above mentioned may be expected. A similar developer may with great advantage be used in making nega- tives of line subjects. Gelatine slides should certainly be varnished…
Slides (Photography)
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
