Safety film originated about the 1920s. Nitrate was
discontinued for motion picture stock in 1951. Some nitrate sill
film was made after that. 35mm film has frame markings that tell
which kind of stock its on. The marks run laterally for nitrate
and longitudinally for safety film. I am not sure when Kodak
discontinued nitrate for still film but it was earlier than other
makers.
Unless you have very old film there is not much chance of its
being on nitrate stock. There are various tests for film stock
which can be found on the web.
Heat will soften the emulsion long before it softens the
support and will eventually cause it to slough off the support.
If the film was folded and there is a crease its unlikely
you can remove the crease. You can unfold the film enough to scan
or print it but the crease will leave a mark. The marks can be
retouched. I suggest unfolding the film, clamping it in a glass
holder and either scanning or printing it. Since very extensive
retouching can be done electronically it seems to me that
scanning it is the best way.
The crease will likely have damaged the support mechanically.
When 35mm film has been bent, as when stored looped around itself
it is often possible to straighten it by hanging it using clip
hangers and leaving it for a long period of time, maybe weeks.
Where its in short sections, like roll film probably clamping it
between sheets of glass for long periods can straighten it. It
depends on the elasticity of the material.
I mentioned in an earlier post that acetate film was subject
to decomposition. This is well covered if you search for "vinegar
syndrome". Vinegar syndrome is the combination of effects from
the decomposition of various kinds of acetate film. While
originally of concern to motion picture archives it turns out to
be a problem with all sorts of still films too. As with nitrate
stock the life and vulnerability of acetate varies tremendously
with the manufacturer as well as storage conditions.
BTW, some very early motion pictures exist because the
Library of Congress required paper prints for copyright. The
paper prints survived where the nitrate negatives and prints were
long ago destroyed.
On 3/6/2020 11:29 AM, mark@xxxxxxxxxxxxxxxxxx wrote:
This actually something I had thought about. I wondered if the film was new enough that any form of heat and they might burn. Decided against that because if it was warm enough to flatten, it would be warm enough to distort. Anyone know the time frame safety film came out?
I found a place that would scan them, but they wouldn't do it while I waited, which also meant I couldn't say stop if I saw it going bad. I think they would feed, but really no way to know unless you try. I have also had experience where something out of their ordinary gets set aside and lost.
These are negative, and I can tell some are people. Most likely they are vacation snapshots, but hard to know for sure. There is always film rescue, and if I knew what was on it, might be worth it, but with these its unlikely to be that important. Then again, I have been surprised before.
Found a roll of film once that appeared in a bag that had been sitting in various places. When processed it turns out it was taken on maybe the second date with my now wife of many years. It had sat in the bag for about ten years, so I will always wonder just how well they might have come out had they been promptly processed.
-------- Original Message --------
Subject: [pure-silver] Re: Old film that needs to be flattened
From: `Richard Knoppow <dickburk@xxxxxxxxxxxxx
<mailto:dickburk@xxxxxxxxxxxxx>>
Date: Thu, March 05, 2020 5:47 pm
To: pure-silver@xxxxxxxxxxxxx
<mailto:pure-silver@xxxxxxxxxxxxx>
You are correct, "safety film" refers to cellulose acetate
film as opposed to cellulose nitrate film. Nitrate burns
intensely and provides its own oxygen so is very difficult to
extinguis. Also, once nitrate begins to decompose it can
combust
spontaneously. Acetate film will support flame but will not
spontaneously combust.
Nitrate motion picture film has not been made since 1951
and
most other formats on nitrate were discontinued long ago. 16mm
and 8mm motion picture film were _never_ made on nitrate base.
It is the color sensitivity of the emulsion that determines
if it can be processed using a safe light. Plain emulsions are
sensitive to blue and near UV and orthochromatic emulsions
are,
in addition, sensitive to green and sometimes yellow light.
They
can be processed under a red safelight although some ortho
films
have enough far yellow sensitivity to require a very weak red
light or restricted time. Panchromatic emulsions are
sensitive to
red light and can be processed only in total darkness. Some
can
be processed in very dim green light for short periods of
time.
The green light of a color where the sensitivity of the dark
adapted eye is at its maximum. In addition many panchromatic
films have a dip in their sensitivity to green light.
There are desensitizers that reduce the red sensitivity of
pan film and allow more extended processing under a rad
safelight.
Now, since I am being wordy, the method of processing will
have no effect on this film. The problem is that its been
bent or
folded beyond the elastic limit of the support. While film
support does absorb some moisture it is not like the emulsion,
which absorbs a lot. Soaking it may result in softening the
emulsion enough to cause it to separate from the support.
If you
want to experiment with floating it onto a new support this
may
be useful but otherwise I think it will make a difficult
problem
worse.
On 3/5/2020 2:41 PM, Ken Hart wrote:
>
> Unless I'm mistaken (I've been mistaken before!), "safety
film"
> refers to the flammability of the film base, and has
nothing to
> do with a safe light for processing.
>
> From Google/Wiki: "Cellulose acetate film, or safety
film, is
> used in photography as a base material for photographic
> emulsions. It was introduced in the early 20th century by
film
> manufacturers and intended as a safe film base
replacement for
> unstable and highly flammable nitrate film."
>
> Ken Hart
> kwhart1@xxxxxxxxxxxx <mailto:kwhart1@xxxxxxxxxxxx>
> On 3/5/20 4:50 PM, mark@xxxxxxxxxxxxxxxxxx
<mailto:mark@xxxxxxxxxxxxxxxxxx> wrote:
>> Had that happen once too. In that case though I knew
what was
>> on it, and although there might have been some interesting
>> flower pictures lost, that would not be nearly as bad a
losing
>> one that had your great grandmother on it when she was
young.
>>
>> I'm wondering if a film scanner that feeds from the
sprockets
>> could get the film flat enough. My flat bed with its
holder I
>> am sure wouldn't. Got two labs that might be able to do
it.
>> Anyone recognize 3LIM or 31IM? It is a safety film, which
>> might mean this film could have been processed under a safe
>> light. My search has turned up nothing. Just knowing that
>> might be an important piece of information.
>>
>> -------- Original Message --------
>> Subject: [pure-silver] Re: Old film that needs to be
flattened
>> From: "Laurence Cuffe"
>> <dmarc-noreply-outsider@xxxxxxxxxxxxx
<mailto:dmarc-noreply-outsider@xxxxxxxxxxxxx>
>> <mailto:dmarc-noreply-outsider@xxxxxxxxxxxxx>> (Redacted
>> sender "cuffe" for DMARC)
>> Date: Wed, March 04, 2020 7:06 pm
>> To: pure-silver@xxxxxxxxxxxxx
<mailto:pure-silver@xxxxxxxxxxxxx>
>> <mailto:pure-silver@xxxxxxxxxxxxx>
>>
>>
>>
>>> On 5 Mar 2020, at 00:21, mark@xxxxxxxxxxxxxxxxxx
<mailto:mark@xxxxxxxxxxxxxxxxxx>
>>> <mailto:mark@xxxxxxxxxxxxxxxxxx> wrote:
>>>
>>> Doing a project with very old family photos. I have a
>>> strip of 35mm negative that on it says safety ILM 3 I
>>> think it is, but that isn't the biggest problem. It was
>>> over the years creased like paper that had been folded.
>>> Some of the folds are through the middle of the image.
>>> Any way to flatten.
>>>
>>> I have no idea what is one them. Judging from the prints
>>> found with it, I would wager a best guess of about 50
>>> years. They don't appear to be scratched up.
>>>
>>> First idea is to contact print them with glass on top to
>>> see what I have. I could probably copy them from a
>>> contact print, but would rather have the wet print if
>>> possible. Would leaving them sandwiched between two
>>> plates of glass with some weight on top do any good.
>>> Though about soaking them, but thought better of that
>>> pretty quickly. Might or might not help. Ideas and
>>> thanks everyone
>>
>> I’d second your instinct that soaking might not be ideal.
>> I have had some poor experiences where old emulsion just
>> sloughed off the substrate when trying to clean old
>> negatives with water.
>> Best
>> Laurence Cuffe
>>
>>
>>>
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-- Richard Knoppow
dickburk@xxxxxxxxxxxxx <mailto:dickburk@xxxxxxxxxxxxx>
WB6KBL
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