emulsion 
base Schicht 
  
receiver 
     
  
  
   
       
  
  
  
  
  
à zu | Schichttrager fj 7^ Fring NM 
rial -—N — f/ = 
o: =A : E: x Rl an 
: , 
a) b) c) d) 
Fig.1: Arrangements for measuring the transmission density (after American 
National Standard PH2.19-1959 Diffuse Transmission Density). 
The density values obtained by means of these arrangements are 
tio called: ; t 
e a) and b) totally diffuse density. Both arrangements furnish the 
same results; the supplement "totally" is only valid for the strict 
ns observance of the conditions; in practical, approximated cases the 
mm (9 supplement is left out. 
C) specular density. 
d) double diffuse density. 
In b) and c) the parallel incident light is often realized with 
= an angle of 2 Qi. 
& 
2 
5 
TU 
d m 
E 
on C 
all 20 
specular | gerichtete 3 
density K" Dichte (c) double 
optische diffuse ass 
Dichte density ) 
i (b) (d) 
(9 be 2 
LL 1 11-130 E I [LL I. 
oc; 28 mm. 25%. 5% 30% 50° 70° 90°. ou; 
00 19. 2,5309 750°, 709 909 9097 —- 777-7 909 a, 
tice 
llu- É 
e. Fig.2: Density of a high sensitive, coarse-grained film material as 
function of the measuring geometry for three pieces of film of 
different density (after Thomas 1973, p. 839). On the left the 
axis angle of the illuminating light is a. = D ro - const; the 
axis angle of the receiver varies from a, = 1° to 90°. On the 
‘right the axis angle of the receiver is a’, = 90° = const and 
the axis angle of the incident light varies from a. = 5° to 90°. 
ng The letters in brackets indicate the measuring geometries 
graphed in fig.1.