What happens to film as it ages?

"jjs" wrote in message ...
"Richard Knoppow" wrote in message
...

Freezing pretty well stops any chemical changes in the film. Frozen
film will stay "fresh" for decades.

Richard, did you catch the earlier conversation in which people asserted
that cosmic radiation (of various sorts) will fog film regardless of
freezing down to Zero F? Seems like bull to me.

It isn't. Gamma rays, bubba...

Jean-David Beyer wrote:

Richard Knoppow wrote:


Freezing pretty well stops any chemical changes in the film. Frozen
film will stay "fresh" for decades.

I hate to contradict Richard, but I had some 4164 TriX and 4147 PlusX that
were stored in a freezer for about 2 decades, and the EI dropped to about
1/4 the box speed and the fog level about tripled. That ended my
stockpiling film for the long term. Now the freezer worked, and was set
around 0F. This was in New Jersey, and I do not know if the radioactive
leaks from our nuclear power plants did it, or the contaminated air that
got through those plasticized inner bags, or what, but it happened
nonetheless.

Interesting! I wonder if that's what's wrong with my Delta 100? I shot
a couple rolls recently that I'd had stored for a long time in the
freezer in double plastic freezer bags plus the cellophane around the
brick of film. Thawed it gradually as usual, and when I exposed it at
its normal ISO, got negs that were barely exposed at all. Made only the
faintest image on the film. I had been chalking it up to something I
screwed up in mixing my developer, but now I'm wondering if I simply
lost film speed due to five years in the freezer. I'll have to test
some other rolls from the brick and shoot them at different speeds.

LR Kalajainen wrote:
Jean-David Beyer wrote:

Richard Knoppow wrote:


Freezing pretty well stops any chemical changes in the film. Frozen
film will stay "fresh" for decades.

I hate to contradict Richard, but I had some 4164 TriX and 4147 PlusX
that were stored in a freezer for about 2 decades, and the EI
dropped to about 1/4 the box speed and the fog level about tripled.
That ended my stockpiling film for the long term. Now the freezer
worked, and was set around 0F. This was in New Jersey, and I do not
know if the radioactive leaks from our nuclear power plants did it,
or the contaminated air that got through those plasticized inner
bags, or what, but it happened nonetheless.

Interesting! I wonder if that's what's wrong with my Delta 100? I
shot a couple rolls recently that I'd had stored for a long time in the
freezer in double plastic freezer bags plus the cellophane around the
brick of film. Thawed it gradually as usual, and when I exposed it at
its normal ISO, got negs that were barely exposed at all. Made only
the faintest image on the film. I had been chalking it up to something
I screwed up in mixing my developer, but now I'm wondering if I simply
lost film speed due to five years in the freezer. I'll have to test
some other rolls from the brick and shoot them at different speeds.

I do not know about 5 years. My film had been frozen from new for almost
20 years, so at least 10 years out of date.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 20:45:00 up 22 days, 7:50, 4 users, load average: 4.30, 4.25, 4.19

LR Kalajainen wrote:
Jean-David Beyer wrote:

Richard Knoppow wrote:


Freezing pretty well stops any chemical changes in the film. Frozen
film will stay "fresh" for decades.

I hate to contradict Richard, but I had some 4164 TriX and 4147 PlusX
that were stored in a freezer for about 2 decades, and the EI
dropped to about 1/4 the box speed and the fog level about tripled.
That ended my stockpiling film for the long term. Now the freezer
worked, and was set around 0F. This was in New Jersey, and I do not
know if the radioactive leaks from our nuclear power plants did it,
or the contaminated air that got through those plasticized inner
bags, or what, but it happened nonetheless.

Interesting! I wonder if that's what's wrong with my Delta 100? I
shot a couple rolls recently that I'd had stored for a long time in the
freezer in double plastic freezer bags plus the cellophane around the
brick of film. Thawed it gradually as usual, and when I exposed it at
its normal ISO, got negs that were barely exposed at all. Made only
the faintest image on the film. I had been chalking it up to something
I screwed up in mixing my developer, but now I'm wondering if I simply
lost film speed due to five years in the freezer. I'll have to test
some other rolls from the brick and shoot them at different speeds.

I do not know about 5 years. My film had been frozen from new for almost
20 years, so at least 10 years out of date.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 20:45:00 up 22 days, 7:50, 4 users, load average: 4.30, 4.25, 4.19

"Jean-David Beyer" wrote in message
...
LR Kalajainen wrote:
Jean-David Beyer wrote:

Richard Knoppow wrote:


Freezing pretty well stops any chemical changes in the film. Frozen
film will stay "fresh" for decades.

I hate to contradict Richard, but I had some 4164 TriX and 4147 PlusX
that were stored in a freezer for about 2 decades, and the EI
dropped to about 1/4 the box speed and the fog level about tripled.
That ended my stockpiling film for the long term. Now the freezer
worked, and was set around 0F. This was in New Jersey, and I do not
know if the radioactive leaks from our nuclear power plants did it,
or the contaminated air that got through those plasticized inner
bags, or what, but it happened nonetheless.


I rather doubd radiation fron the nuclear plant caused any
problems. The shielding is good enough to stop the particles causing film
degredation. I would guess there was a chemical degredation in this case
from something in the freezer. Several "normal" gasses will cause this and
in a confined space the effect would be intensified. Over a l-o-n-g time
cosmic rays will cause damage. And how can one know for sure about the
condition of the film before freezing?

Interesting! I wonder if that's what's wrong with my Delta 100? I
shot a couple rolls recently that I'd had stored for a long time in the
freezer in double plastic freezer bags plus the cellophane around the
brick of film. Thawed it gradually as usual, and when I exposed it at
its normal ISO, got negs that were barely exposed at all. Made only
the faintest image on the film. I had been chalking it up to something
I screwed up in mixing my developer, but now I'm wondering if I simply
lost film speed due to five years in the freezer. I'll have to test
some other rolls from the brick and shoot them at different speeds.

Do you have a freezer dedicated to photographic film? Film packs
are perfectly sealed from light but not gasses. I've had paper fogged by
being in the presence of very dilute sulfur dioxide (please don't ask).

I do not know about 5 years. My film had been frozen from new for almost
20 years, so at least 10 years out of date.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 20:45:00 up 22 days, 7:50, 4 users, load average: 4.30, 4.25, 4.19

I have now bought out the stock of Kodak and Ilford film and paper from
every vendor within driving range and stored it in the bomb shelter I built
in the '60s, used for fuel oil in the '70S, converted to a disco in the
'80s, and gold and currency in the '90s. I have sufficient amount at least
for my great grandchildren, unless The Flood comes ;-)

dr bob.

"jjs" wrote in message
...
"Richard Knoppow" wrote in
message ...

Freezing pretty well stops any chemical changes in the
film. Frozen film will stay "fresh" for decades.

Richard, did you catch the earlier conversation in which
people asserted that cosmic radiation (of various sorts)
will fog film regardless of freezing down to Zero F?
Seems like bull to me.

Cosmic rays do cause some fogging but mostly on fast film.
I don't think they have any effect on paper emulsions. Most
of the degradation of film comes from continuation of the
ripening process and from other slow chemical changes in the
emulsion. Freezing should slow this down very considerably
but it may still go on. Some polutants can cause rapid
damage to the emulsion. Strong oxidizers and sulfides are
particular examples. Sulfide, for instance, is an important
sensitizer but in excessive amounts is a very prodigeous
fogging agent. That is why it is recommended that sulfiding
toners not be used where unprocessed film or paper is
stored.
I can't explain the problems with the frozen film but
this does not seem to be the common experience with it.


--
---
Richard Knoppow
Los Angeles, CA, USA

"jjs" wrote in message
...
"Richard Knoppow" wrote in
message ...

Freezing pretty well stops any chemical changes in the
film. Frozen film will stay "fresh" for decades.

Richard, did you catch the earlier conversation in which
people asserted that cosmic radiation (of various sorts)
will fog film regardless of freezing down to Zero F?
Seems like bull to me.

Cosmic rays do cause some fogging but mostly on fast film.
I don't think they have any effect on paper emulsions. Most
of the degradation of film comes from continuation of the
ripening process and from other slow chemical changes in the
emulsion. Freezing should slow this down very considerably
but it may still go on. Some polutants can cause rapid
damage to the emulsion. Strong oxidizers and sulfides are
particular examples. Sulfide, for instance, is an important
sensitizer but in excessive amounts is a very prodigeous
fogging agent. That is why it is recommended that sulfiding
toners not be used where unprocessed film or paper is
stored.
I can't explain the problems with the frozen film but
this does not seem to be the common experience with it.


--
---
Richard Knoppow
Los Angeles, CA, USA

"jjs" wrote in message
...
"Richard Knoppow" wrote in
message ...

Freezing pretty well stops any chemical changes in the
film. Frozen film will stay "fresh" for decades.

Richard, did you catch the earlier conversation in which
people asserted that cosmic radiation (of various sorts)
will fog film regardless of freezing down to Zero F?
Seems like bull to me.

Cosmic rays do cause some fogging but mostly on fast film.
I don't think they have any effect on paper emulsions. Most
of the degradation of film comes from continuation of the
ripening process and from other slow chemical changes in the
emulsion. Freezing should slow this down very considerably
but it may still go on. Some polutants can cause rapid
damage to the emulsion. Strong oxidizers and sulfides are
particular examples. Sulfide, for instance, is an important
sensitizer but in excessive amounts is a very prodigeous
fogging agent. That is why it is recommended that sulfiding
toners not be used where unprocessed film or paper is
stored.
I can't explain the problems with the frozen film but
this does not seem to be the common experience with it.


--
---
Richard Knoppow
Los Angeles, CA, USA

On 10/14/2004 6:21 AM jjs spake thus:

"Richard Knoppow" wrote in message
...

Freezing pretty well stops any chemical changes in the film. Frozen
film will stay "fresh" for decades.

Richard, did you catch the earlier conversation in which people asserted
that cosmic radiation (of various sorts) will fog film regardless of
freezing down to Zero F? Seems like bull to me.

Huh? Say what? How would freezing stop fogging due to cosmic radiation? Once
the "rays" (particles) hit the film, it's fogged, regardless of temperature.
Freezing ain't gonna stop that.


--
Everybody's worried about stopping terrorism. Well, there's a
really easy way: stop participating in it.

- Noam Chomsky

"Marco Milazzo" wrote in message
...
Thanks for lots of good information here. A follow-up
question:

I noticed that the outdated film I shot looks fogged. Is
fog ever
desirable, or is it always undesirable?

For instance, Ansel Adams recommends pre-exposure (you
might say
"pre-fogging") for certain contrastry situations. Is aged
film fog
the same thing -- or is it always a degraded image?

TIA,
Marco

A pre-exposure will lower contrast on some films and can
be used to increase speed for long exposures but it is
unpredictable. Some emulsions loose contrast as they age but
not because of fog. Its due to the chemical changes I
mentioned in an earlier post. The chemistry of the emulsion
is very complex. Emulsions are well stabilized but are not
perfectly stable so they will change over time. The
expiration date is usually the manufacturer's estimate of
how long the film can be counted on to deliver the
performance specified in its data sheets given "average"
storage conditions. Heat accelerates chemical reactions
including those in the emulsion so storing film or paper
where its cool will extend its life. Moisture is another
problem but will not affect unopened packages of film or
paper. Its possible that freezing can damage the emulsion in
some way. Remember that moisture is driven out by freezing.
Think about the effect of freezing on food. It may stay
unspoiled for long periods of time but may not taste the
same.


--
---
Richard Knoppow
Los Angeles, CA, USA