On the Test of a Polyester Aerial Photographic Film T-008 
121 
negative and diapositive films are spreaded by the pressure and the 
warmth in the printer. 
c) The shrinkage of CNT diapositives, which are printed from TAC 
negatives, is much smaller than that of TAC negatives. Its reason 
have not been yet clear, but this phenomena can be solved, similar 
to the assumption for b), if we assume that the TAC negatives 
recovered their sizes at the printing of diapositives by the pressure 
and warmth of the printer. 
d) By the ratio of a v la n we can conclude that the geometrical accuracy 
decreases with the repetition of printing procedures. 
d. The differences of the longitudinal and lateral shrinkages were measured 
with the pin-gauge for the new film and KOK film. 
By the comparison of the result shown below, we can conclude that PET 
film is much better than TAC film in this respect too. 
Table 9. Difference of longitudinal (X) and 
lateral (Y) shrinkage 
Direction 
PET 
TAC 
X 
0.0002 
0.0004 
Y 
0.003 
0.005 
X~Y 
0.0028 
0.0046 
6. Comparison of physical properties 
Comparison of the physical properties of PET and TAC films is shown on 
the following table. 
Table 10. Physical properties of PET and TAC films 
Film 
Folding 
strength 
Tensile 
strength 
Elongation 
Tearing 
strength 
Young’s 
modulus 
PET 
10,000< 
*2,500< 
20 kg/mm 2 
160% 
160g 
*50-60 
dyne/cm 2 
1.8X10 3 
TAC 
45-50 
*2-20 
11 
35 
40 
*21-36 
3.6X10 3 
Film 
Coefficiency of hygrometric 
expansion (1% R.H.) 
Shrinkage after 
processing 
Mean 
Affinity 
Mean 
Affinity 
PET 
0.0028% 
0.0002% 
0.014% 
0.003% 
TAC 
0.0084 
0.0004 
0.040 
0.005 
Remarks: 1) Development: D-76, 20°C, 12 min., Fixing: FFH-4, 20°C, 10 min., Wash 
ing: Running water, 16°±1°C, 20 min., Drying: 23°C, 67% R.H. 2) * Low temper 
ature test (-20—24°, 100% R.H.)