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RE: filmscanners: Sharpness of color chrome vs color negative.




> Kodak and Fuji publish MTF specs on their films. Check their web sites.

Fuji does provide MTF for both their positive and negative film, Provia 100
and Superia 100.  There is also additional information besides the MTF
provided, like resolving power and diffuse RMS granularity value.  The
problem I am having with the numbers provided, is I must not be
understanding them completely.

I know that the RMS granularity for chrome film has to be divided by
2.5...that would make them equal (Provia is 10, divided by 2.5 = 4, and
Superia is 4.  OK, so that's a wash...  Then, the resolution shows that at
1000:1, Provia resolves 140 lines/mm and Superia 125.  That would mean that
Provia (positive film) has a HIGHER resolving power than Superia (negative
film)...BUT, wait...there's more.

The MTF for Provia falls off at around 60, and the MTF for Superia falls off
at ~130.  That, to me, means Superia is FAR superior at resolution than
Provia....  OK, so why the discrepancy?




 




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