Nipher — Relation of Direct to Reversed Photographic Pictures. 55 



Diagram I. 



E 



k 



zero condition 



3000 



2000 



• in 



d' 



1000 



d 



TTT 



7 6 5 



0.1 



T 



2.5 



0.2 



2 r 



Ordinates represent exposure in lamp-meter-seconds. Lamp = 16 candle 



power. 

 Abscissae represent illumination of the plate while in the developing bath, 



in lamp-meters. 

 The rectangular area within the zero line, covers the conditions yielding 



negatives. External to this line is the region of positives. 



