# How long does exposed film stay good?



## Sw1tchFX (Dec 1, 2007)

I shot Mt. Hood on some TMAX 100 in august (at 5-7am to catch the sunrise off of Lake Trillium), I sent it to the lab yesterday. 

It's been in the canisters, in my car for the last 4 months and I'm 99% sure it's fine, but I just need some filling in for that last 1%. The only thing i'm worried about is precipitation, I'm pretty sure it was wet and I know it was chilly and those canisters just lock in (or lock out) everything.


----------



## Sideburns (Dec 1, 2007)

well...the temperature change couldn't have been great for it (being in a car and all)...but something will come out...lol


----------



## Sw1tchFX (Dec 2, 2007)

yeah, i'm not to worried about it, I can always go back. It's only 45minutes away.


----------



## nealjpage (Dec 2, 2007)

I'm sure it'll be fine, Switch.  It doesn't get _that_ hot in PDX.

Now, for that old roll of Verichrome that's been in my grandpa's Brownie Hawkeye since 1955...that's another story!


----------



## Alex_B (Dec 2, 2007)

i had various types of exposed slide film with me while travelling for months, also in very hot climate. none of them had any problem afterwards.

but temperatures in cars can get quite extreme ... not sure there.

wait and see


----------



## Sw1tchFX (Dec 2, 2007)

mkay, thanks for the info!


----------



## malkav41 (Dec 2, 2007)

I had some film developed that I had shot over 13 years ago. and it came out fine. 
It had been stored both in the house, and in a storage building that was not temperature regulated for about 6 months in Texas.


----------



## Sw1tchFX (Dec 3, 2007)

nice, that's good to know! :thumbsup:


----------



## Helen B (Dec 3, 2007)

Latent image keeping properties vary quite a bit from film to film. In general any problems show up in the shadow detail - because weak latent image centres (ie those composed of very few silver atoms) are the least stable (it's a little bit like reciprocity failure). Very fast films, and those with special sensitisation, seem to be more affected than slow and medium speed films.

My observations have been that Tri-X and Kodachrome will stand a lot of abuse before there is _measurable_ loss of latent image and that Agfa APX 400, Kodak HIE and most very high speed films are the worst - like T-Max P3200, Delta 3200, Ektachrome P1600 etc. (I can only report on films that I have extensive experience of in hot conditions, mainly in SE Asia.)

APX 400 was the odd one out - most 400-speed films seemed to be OK. Even a three-month delay in the tropics lead to very noticeable loss of image detail and a change of image quality with APX 400.

T-Max P3200 and Delta 3200 really need to be developed as soon as possible after shooting for the best shadow detail, though the loss resulting from a delay will not be all that obvious.

Best,
Helen


----------



## Alex_B (Dec 3, 2007)

oh, just remember one disaster ... had some AGFA consumer grade slide film which I carried around in Japan in the humid season ... and after developing tiny parts of the emulsion just fell off!!!


----------



## mysteryscribe (Dec 6, 2007)

In the tropics Alex I have had heavy leather boots fall apart film emulsion isn't a shock at all.


----------



## Alpha (Dec 6, 2007)

Helen B said:


> My observations have been that Tri-X and Kodachrome will stand a lot of abuse before there is _measurable_ loss of latent image



Perhaps I'm nit-picking here, but don't you mean noticeable, and not measurable? And by noticeable I mean by eye. As far as measurable differences, latent image loss tends to be linear, as opposed to curvilinear. As such, a sensitive-enough densitometer would be able to measure loss before it was apparent to the naked eye. I believe that the slope of the line for density vs time simply differs between films, and not necessarily the curvature. That is, under constant environmental conditions, those films which begin to lose their latent images more quickly will continue to lose them at a similar rate. Perhaps this is something that could be better clarified by the APUG crowd.


----------



## Helen B (Dec 6, 2007)

MaxBloom said:


> Perhaps I'm nit-picking here, but don't you mean noticeable, and not measurable? And by noticeable I mean by eye. As far as measurable differences, latent image loss tends to be linear, as opposed to curvilinear. As such, a sensitive-enough densitometer would be able to measure loss before it was apparent to the naked eye. I believe that the slope of the line for density vs time simply differs between films, and not necessarily the curvature. That is, under constant environmental conditions, those films which begin to lose their latent images more quickly will continue to lose them at a similar rate. Perhaps this is something that could be better clarified by the APUG crowd.



Believe it or not I chose my words very carefully - as I try to do with almost all my posts. That is why I italicised 'measurable'. I just don't always manage to get my meaning very clear, espeially when trying to be brief. I have a sensitive densitometer, and was trained in sensitometry, the various methods of testing film, and all that stuff by Kodak. If it is done carefully enough, and with better equipment than I have at hand, you can measure latent image loss after about five minutes. I did make an unwritten assumption that any immediate latent image loss is neglected for my comments on Kodachrome and Tri-X. In a strict sense you are correct that measurable latent image loss is almost immediate, but I'm not sure that that is of practical importance. I was trying to distinguish between those films that showed easily measurable loss, but no noticeable loss; and the films that showed no significant loss whether measurable or noticeable.

As I mentioned, latent image loss tends to hit the latent image sites with the fewest silver atoms first. From what I have observed, the rate of latent image loss appears to decrease with time, so you may be able to measure, or even see, the difference between a film developed within a day or less and one delayed by a month, but there will be little change between one developed after a month and one developed after three months. It varies a lot from film to film.

The clusters of silver atoms that are small enough to be at the limit of developability are not very stable. Many factors affect the stability of the latent image centres, including whether or not the latent image centre is superficial or internal, and whether it was created by an excited dye molecule or not (ie the wavelength has an effect - the presence of a dye molecule with a positive hole tends to be a bad thing, because 'Dye+' can get an electron back from a silver atom). This whole stability issue is also related to reciprocity failure and latensification by low intensity light. I won't mention Tani's proof of Lowe's hypothesis for the behaviour of positive holes in the presence of R centres, because this is a family forum.

I'm happy to explain my comparatively limited understanding of all this (limited in comparison to real emulsion engineers like PE/RM) further, if you or anyone else is interested. 

Best,
Helen


----------

