| abstract |
A base film for photographic films, characterized by (a) having a refractive index (nz) in the thicknesswise direction of at least 1.498, (b) having a haze value of 2.0 % or less, (c) having one direction wherein a tan delta value at 80 DEG C due to the tensile viscoelasticity at 0.05 Hz is 0.09 or less, (d) having a curling resistance ratio of 70 DEG C of 45 % or above, (e) having a thickness of 40-120 mu m, and (f) substantially comprising polyethylene 2,6-naphthalenedicarboxylate. This base film has various performances suitable as photographic films, such as curling resistance, transparency and slipperiness. |