Pringle, Andrew · New York : Scovill & Adams Company of New York · leaf 78
cape negatives. In reducing, our routine is as follows : Reduce the landscape, shading the sky — if the negative sky is not dark enough — with the sky mask ; shut the dark slide ; put cloud negative into the position lately occupied by landscape negative; open the dark slide and expose again,…
Slides (Photography)
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.