Finding unboxed film expiration dates

[mattbellphoto]

I've shot with expired film plenty and pretty-much know what results to expect and what (ISO) adjustments to make based on the age of the film, etc..
But this only goes for film still in its box or with vender information.

What I would like to know is: How can one find the (approximate) age of rolls with missing expiration date info? Mainly to determine whether the film is usable vs. usable with fogging/color shifts vs. kaput.

Ways I think that may work, but do not know how to apply:
(These judgements are to be based on the assumption that film was stored at room temp and normal humidity.)
-brittleness of film
-discoloration of the film leader (compared to film inside 35mm cartridge)
-package design / branding
-ambiguous numbers/info written on cartridges

I would like to put together a comprehensive source on methods/info..
I've Googled and searched APUG and Photo.net but have not found one.

 

[frobozz]

Well if you have a bunch of any particular kind, the edge printing after development might give some more clues... batch codes, etc. Obviously that doesn't help much for the one-off roll you might have.

Duncan

 

[holmburgers]

The discoloration of leader is probably a relatively good method, but might depend on variables other than simply age, namely light & heat. But, of course these things play just as important of a role as time does. I have some very old (no idea to be exact) TMAX 400 in bulk rolls, and I can say that the leader is significantly lighter than the inside film.

Package design is probably going to be the best bet, and it would be cool to get a database of that.

 

[CGW]

It's the chief reason I never buy unboxed, loose 35mm film. With 120, stale dates are always imprinted on the wrapper which gives a bit of confidence, even if storage conditions are a mystery.

 

[perkeleellinen]

Some UK suppliers break down pro packs and sell films individually. I've got a lot of 800Z like this and it's in date but I don't know when it expires. I wrote to Fuji UK asking them if they could date the film by the small serial number printed right next to the film gate and they told me no. All they could give me was two dates of the two batches they'd imported. I think stuff like package design and leader condition is only relevant for quite old film, not stuff that's either in-date or just out of date.

 

[hpulley]

If you can sacrifice a bit of the film, pull some out in a changing bag and develop it to get the edge numbers. You may need to re-trim the leader so it will load properly. This will at least tell you what it is and you may be able to look up the batch numbers and find out how old it is.

Barring that, if the film is Fujicolor and fairly recent it has red, green and blue in the edge markings which you can test develop to look for color shifts and fogging. I assume you mean color here as B&W you can obviously test develop to check for base fog but it is more complicated with color as you know.

 

[ic-racer]

It shouldn't matter if the film box is marked or not, the method is the same as any unknown film. Here are the results of a roll of bulk Delta 400 I got from a friend last week. The base was 0.66 and the speed was 160.