At 07:16 PM 7/16/03, Albert asked:
OK, someone set me straight..
Fine grained means the grain size is small; high resolution means it
resolves a lot more?
Except in my head, I keep thinking, if the grain is smaller, the
resolution should be higher??
Or are they mutually exclusive?
No, they're not mutually exclusive. The are related. However, resolving
power of the film is depicted by its Modulation Transfer Function, or
MTF. If you want to know the capability of a particular film to record
detail level, the MTF graph for that film contains the necessary
information. Knowing how to interpret one, and compare the graphs for
different films is another matter. The MTF is a combination of resolution
capability and contrast. Without sufficient contrast, resolution cannot be
discerned. If either is taken to an extreme, the other will be
compromised. It is better to think in terms of accutance, which is ability
of a human to detect recorded details. They may be present, but if the
human eye cannot detect it, it's as if they're not.
A logician/mathematician would tell you:
If high resolving power, then very fine grain. However it's not an "if and
only if" relationship.
Likewise a scientist would tell you:
Very fine grain is a necessary, but not a sufficient condition for high
resolving power.
In layman's terms:
A high resolving power film will have very fine grain. However, a film
with very fine grain does not necessarily have high resolving power. Most
do though. Very fine grain is an enabler, but not the only factor in film
resolving power. Grain shape, physical emulsion structure and
contrastiness of the emulsion chemically are also factors.
Velvia shows better accutance in its MTF curve compared to Provia 100F,
even though Provia 100F is slightly finer grained (emphasis on
slightly). Likewise, Kodachrome 64 has higher accutance than most ISO 100
E-6 films because of its emulsion structure, even though most of the ISO
100 E-6 films are slightly finer grained.
-- John
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