By simple comparison of the measurements, the dimensional stability of the emulsion 
on the aerial films under investigation could then be checked in a positive way. 
All measurements were carried out in a room equipped with air conditioning, keeping 
the temperature at 68° F and the relative humidity at 70 % 
Results: 
/0* 
a) The maximum differences between the cross and longitudinal shrinkage, measured 
on 8 em (ab. 3”) stretches, varies between — 74 and + 59 microns, according to the 
type of film used. On plates, this difference amounts to about 7 microns; 
b) 
each pictur 
the mean random longitudinal shrinkage, as taken over six stretches 8 cm long on 
e, ranges between 4-6 and 4- 17 microns according to the type of film; on 
plates, it amounts to only 4- 2 microns; 
the mean r 
between + 
andom cross shrinkage in 6 stretches, 8 cm long on each picture, ranges 
6 and +23 microns, according to the type of film used; on the plates it is 
+ 3 microns; 
the mean random shrinkage on all measured stretches, in the longitudinal, cross, and 
diagonal directions, falls somewhere between + 11 and 4- 14 microns; in plates, it 
amounts to only + 3 microns; 
the maximum difference between two adjacent stretches, 8 cm (about 3”) long, taken 
in the same direction, is between 13 and 16 microns; on plates this will amount to 
4 microns only. 
The irregularities between adjacent stretches are particularly troublesome because the 
means used to 
compensate for them in plotting are very unsatisfactory, calling as they 
do for changes in the orientation elements. 
  
pP 
+ 204 B-L 
+ 10 + 
10 20 30 40 
Oo FI ; 1 L A 1 L i 
\ 1 I T i 
Li (WW, 
X 
—204 W/, I 
à IM. PAN 4 
ZA à IAN, A 
NEAN M Rove NRI. A A 
-4« VL VON EN AN VN X Lt 
v J A NN N 1 LA 
— o4 N/A VAN > A 
V SNL X ND SS 
V v X eL. M NA 
— 604 N v wo. 
  
  
Fig. 1 
The films under investigation all proved of substantially the same value, however they 
showed some variations in their distortion. 
The emulsions 
on glass plates have more favorable shrinkage properties in every respect. 
The ratio is of some 1:3 to 1:4 in favor of the plates.