[filmscanners] Re: 3 year wait

["Anthony Atkielski" <anthony@atkielski.com>]

Laurie writes:

> I believe that this is truer for medium format
> and large format film s than it is for 35mm
> format films, where the additional true optical
> ppi is important if one wishes to enlarge the
> frame to 16 x20 and larger sizes ...

This is true only if the emulsion used can hold details visible only at
higher resolutions.

In other words, if you are scanning T-Max P3200, you won't get any more at
4000 dpi than you do at 2700 dpi, and so if 35mm doesn't provide enough
detail, you have no choice but to go to a larger format.

If you are scanning Velvia or Kodachrome, you can occasionally obtain more
detail than is fully resolved by a 2700-dpi scanner, especially on a tripod.
In this case you gain a little by scanning at higher resolution, and your
comment above is applicable.  If you are scanning Technical Pan, there is a
_lot_ of detail that is not visible at 2700-dpi (assuming you used a
tripod), and you can go to nearly ten times that resolution figure and still
extract additional information.

For handheld work, it is frequent that detail is no better than 2700 dpi
will resolve, simply because of camera movement.  And even if Velvia will
resolve 120 c/mm in ideal conditions on a tripod, that requires very high
contrast AND a very, very good lens.  A figure of 80 c/mm is more likely,
with an excellent lens, and that requires 4064 dpi.

So you might get a bit more with 4000 dpi than with 2700 dpi for some
photos.  And going further to 4800 dpi might gain you something under
absolutely ideal conditions.  But beyond that, you are just resolving dye
clouds with most emulsions, shooting situations, and lenses.

Put more simply, if you aren't getting enough detail at 2700-3200 dpi from
your 35mm slides, you probably need to go to medium format to get more.  And
if MF isn't good enough, you'll need large format.  The emulsions are all
the same and their resolution is fixed, and good scanners can already pick
up essentially everything they provide in the case of commonly-used emulsion
s, so the only variable you can change to get better images is the area of
film being scanned.

> Only if you are attempting to print uncropped
> 35mm frames at less than 11x14 sizes.

It's independent of that.  The limit is imposed by the emulsion, the
shooting conditions, and the lens on the camera.  It is arguable that 2700
dpi scanners miss a little bit on the best images, but at 4000 dpi or
beyond, this becomes pretty much untenable.  And beyond 4800 dpi, you're
almost always resolving nothing more than additional grain, even with the
sharpest color emulsions.

In the future, we can hope that films will become sharper (as they have
throughout their history), and that lenses will become better (also quite
likely, even though progress is slow).  Scanners are already ahead of the
other elements in the chain, although they'll probably continue to get
better, too.



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