Digital BW, The Print

To answer questions:

 >> and so when the new Artixscan came out with a scan depth
>> of 4.8  (SNIP)
> Is this the 2500F?

The Artixscan 1800 is the one I recommend, it is newer and is the one with
the extended scan depth. I do not recommend the 2500.  The 1800 costs a
thousand dollars less, has a film drawer, and runs circles around the 2500
IMHO.

> So far, the best 35mm film I have found is Kodak
> Portra 400 b&w.  It scans well and looks like Plus X.  Do you have any info
> as to its life refrigerated vs. frozen?

 Portra 400 b&w is not an archival film.  It is chromogenic.  When the Great
Yellow Father speaks of "Excellent Latent Image Keeping" in the sales pitch,
they are referring to the amount of time between exposure of the film and
it's development.  The reason of course is nothing to do with Portra film
itself, the problems of delayed processing of color emulsion film is changes
in color balance, and since Portra has no color this is not an issue.  This
has been known by Kodak for years and is why there are "professional" color
films as well as amateur that are actually the same film, the only
difference is the color balance of a professional color film is adjusted in
manufacture with the idea it will be frozen until use and developed
promptly.  Amateur film is designed to be stored at room temperature and in
the camera up to six months.

As for archival storage of processed chromogenic film, refrigeration (NOT
freezing) is required in order for it to last, however I don't know of
specific life expectancy charts for this particular film.  I would not be
surprised to see a 3-10 year life for the color version of Portra (meaning
15% fade of least stable color layer).  A great analogy is the difference
between dye and pigment printers, that is the difference between single
layer color film marketed as B&W, compared to real silver emulsion B&W.
Here is what Wilhelm has to say about the overall archival considerations of
chromogenic (pg 23) "Among the available color processes, chromogenic films
and prints as a group have the distinct limitation of being relatively
unstable in dark storage.  While most classes of dyes are subject to light
fading, chromogenic dyes are almost unique among commercially available dyes
in that many of them also have poor stability when stored in the dark unless
kept at refrigerated temperatures."  I might add here that EK knows all
about this, and if Portra film had a good life expectancy rating you can bet
they would make a big deal about it.  For details of storage recommendations
for photographers, check Wilhelm's book chapter 19 "Frost-Free Refrigerators
for Storing Color and Black-and-White Films and Prints" or else just go get
a Kenmore true frost free (not cycle defrost). If you don't mind a used one,
they can be had at auctions for $100 or whatever.

best regards, 
Tom Robinson