Nipher — Relation of Direct to Reversed Photographic Pictures. 55 



Diagram I. 



•ft COX': it ion 



(I 



3000 



LOGO 



in 



1000 



I 

 2.5 



3.1 J 



0.2 



i i 



2 »• 



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. 



