U of S | Mailing List Archive | alt-photo-process-l | Re: preservation of negatives/slides/prints

Re: preservation of negatives/slides/prints

Hi Ryuji,

Another factor you don't mention that I'm having to recognize with all gelatin materials here is mould growth. It's especially bad on some trade processed slides, but I also get it on prints and negatives. Humidity is probably the vital factor for this, and I live in a poor area in this respect.

So, despite the problems with digital storage, I think it is vital to get material worth keeping into digital form as soon as possible. Already many of my own images I think important are only printable from the digital files and many of the vintage prints show signs of degradation.



Peter Marshall
petermarshall@cix.co.uk +44 (0)1784 456474
My London Diary http://mylondondiary.co.uk/
London's Industrial Heritage: http://petermarshallphotos.co.uk/
The Buildings of London etc: http://londonphotographs.co.uk/
and elsewhere......

Ryuji Suzuki wrote:
Don't have time to get into details, but the way the film was made,
including the formula for the "film dope" and the way it was filmed has
some influence on the stability of the film as well. Acetic acid is a
relatively weak acid compared to the degradation product of common
plasticizer, triphenyl phosphate (degraded into diphenyl phosphate).
Plasticizer is present at about 1:10 in acetate film and it's a lot. So
the name is "vinegar syndrome" but the reality is probably more

Because these things are rather easily studied by accelerated aging
tests, the formulation has improved since 1980s. It is likely true that
modern triacetate film from Fujifilm and Kodak may be more durable, but
I don't think it is correct to apply findings from modern material to
early cellulose films. Old collections deserve more close attention in
these areas.

Another thing is that it is very misleading to describe one variable as
"the most important factor" etc. here. For b&w silver image, humidity is
an major factor, but even at 30-40% RH, if there is degrading paper or
adhesive in the container, the image may degrade much faster. One must
realize there are several ways to ruin an image just as easily and the
image gets ruined from the weakest mode. It is often the case that the
factors must be prioritized to fit in limited budget, etc., and humidity
is one key factor that should be given a high priority, but a bit of
peroxide from degrading paper or tape can do a big damage as well. It's
not an "or" but rather an "and."

In case of silver image, combination of proper sulfiding toner treatment
can greatly reduce the impact of several variables and it is highly
recommended for anything important.

On Tue, 20 Mar 2007 12:05:36 -0400, "Gawain Weaver"
<gawain.weaver@gmail.com> said:

Hi Richard--
1) That's a good question. IPI did find that "paper envelopes offers no
advantage over plastic to control vinegar syndrome" (Environment and
Enclosures in Film Preservation, Bigourdan and Reilly, 1997).

The question here is two-fold. First, does the plastic sleeve prevent the
acidic degradation products from diffusing away from the film? And
if it does, does it matter? In other words, does the buildup of acid have
any effect on further degradation?

In theory, since acetate base deterioration has been shown to be
acid-catalyzed and auto-catalytic, the buildup of acidic degradation
products will be harmful. However, in real life practice it is not the
determining factor in the life expectancy of film.

My SPECULATION on it goes something like this: There is no significantly
harmful acid-trapping effect from plastic sleeves on acetate film (di or
tri, they're both unstable) that is still in good condition and does not
have increased acidity levels. At this stage acid production is slow
that acid diffusion away from the film is not a significant bottleneck.

Degraded film with high acidity levels will undergo fairly rapid
acid-catalyzed hydrolysis regardless of whether the plastic sleeve
the acid from diffusing away from the film or not. IPI did find that
was a VERY SMALL advantage to be gained by the use of paper envelopes,
it is an insignificant factor if one is concerned with long-term
In the end, deteriorating film needs a cold and dry environment, ideally
very cold and moderately dry (say 0F, 25%RH) to essentially arrest
degradation. Short of such cold storage, any cooler storage with
low RH will be a vast improvement over room temperature. Attempts to
degradation by varying the type of enclosure have proven ineffective.

2) There is no specific risk to scanning, apart from the usual concerns
care and handling. I was simply warning against the casual use of
digitization for preservation purposes.

3) storage materials to avoid-- just the usual-- PVC, cellulose nitrate
acetate (that includes Kodak's triacetate sleeves), glassine, and poor
quality paper are generally to be avoided. Of course, the real
in this case is the Photographic Activity Test, and many enclosures have
passed the PAT and are advertised as having done so. As Ryuji noted,
silver gelatin prints are susceptible to damage by many types of inferior
enclosures and other materials like adhesives. Certainly these things
be taken into account, and good quality enclosures should be used.
The problem however, is that enclosures are a quick and easy fix, and
is a tendency to think that once everything is in a good enclosure that
collection is safe, and this couldn't be farther from the truth. Silver,
nitrate and acetate bases, and color dyes will degrade at room
and moderate RH and or in the presence of common pollutants like sulfur
dioxide, nitrogen oxides, and peroxides. They don't need poor quality
enclosures to degrade. And basements and attics with their extremes of
temperature and humidity will only make matters worse. I trust that Light
Impressions will convince people to use good quality enclosures, but
unfortunately that's not the most important factor by a long shot.


-----Original Message-----
From: Richard Knoppow [mailto:dickburk@ix.netcom.com] Sent: Tuesday, March 20, 2007 2:33 AM

Lots of snipping...
I have a couple of questions. 1, I generally keep negatives in so called archival envelopes or sleeves,
there a problem with these when used for acetate film due to the surfaces
the film being pretty much sealed even though the ends are open?

2, By risk of digitizing for archival purposes do you mean that the
storage of the original material may be ignored or is there a specific
to scanning?

3, Are there storage materials you would specifically warn against?

I always read everything you post>

Richard Knoppow
Los Angeles, CA, USA


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