Finding unboxed film expiration dates
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.