Archival properties and graininess of photographic films

Here at the Australian National Botanic Gardens Herbarium in Canberra,
we routinely take still photographs (in colour and black and white) of
type and historically significant herbarium specimens (an herbarium
specimen being a pressed and dried piece of plant material mounted onto
a board and enclosed by a paper folder).

The colour slide film we had been using until recently was Kodak PKR 120
roll film (a medium format film for use in such cameras as Hasselblads).
We have now found that Kodak no longer process this film type in
Australia - instead the film is sent to the USA or Japan for processing
with roughly a three week turn around time.   Three weeks is too long a
time - we often need to see the results more quickly than that not to
mention the possibility of film going astray.

Kodachrome film is generally regarded as being the most archival - i.e.
it will last longer than other (E6 processed eg. Ektachrome) film
types.  Does anyone know if there exists another brand of medium format
film that has similar qualities of longevity as Kodachrome? Indeed, what
is the difference in life expectancies of a Kodachrome image and an E6
processed image stored under similar conditions anyway?

Whilst on the subject, does anyone have any knowledge of the archival
qualities of the various brands of 35mm B&W films available - Kodak
T-Max particularly?  Until now we have been using Ilford FP4 120 roll
film.  I have a feeling that they are all much of a muchness.  Are the
archival qualities of B&W inherent to the nature of the film, the way in
which it is processed eg. extra washes or some other factor?

We initially chose medium format film because the resulting photograph
would show less grain than the same sized photograph produced from
similarly ISO rated 35mm film.  Given that the photographs we would
produce are about 25 x 40cm, what are peoples experience of graininess
with these two formats?  For example, would two 25 x 40cm photographs,
one taken with 25 ISO 35mm film and the other with 64 ISO medium format
film exhibit similar amounts of graininess?

The reason for asking all this is that should there be no suitable
medium format colour film available we will have to switch over to 35mm
format.  We will continue to use Kodachrome (the 35mm film is still
processed here) as our colour film but would also like some opinions as
to the best 35mm B&W.

All opinions and experiences gratefully accepted!

Andrew Lyne
Herbarium (CBG)
Australian National Botanic Gardens
GPO Box 1777 Canberra ACT 2601  Australia
+61 6 2509 460
Fax: +61 6 2509 599

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                   Conservation DistList Instance 7:8
                  Distributed: Tuesday, June 29, 1993
                        Message Id: cdl-7-8-004
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