SUBJECTIVE SHARPNESS OF IMAGES 



569 



— -^ 0.4 



^-^ 0.8 



.0 S 



1.2 = 



■;;^ 1.4 O 



1.8 D 



2.0 < 



2.2 



2.4 



2.6 



2.8 



3.0 



3.2 



0.5 I 2 5 10 20 30 40 50 60 70 80 90 95 98 99 99.5 



PER CENT OF OBSERVATIONS IN WHICH VARIABLE IMAGE IS JUDGED 

 SHARPER THAN REFERENCE 



Fig. 2 — Distributions of judgments of sharpness differences. The scales of limens 

 denote subjectively-determined units, as explained in the text. Each point repre- 

 sents 45 observations of a small-sized motion picture at a viewing distance of 30 

 inches. 



