What is a problem with expired analog film?
Old expired films indulge very often. How it will work depends on few aspects.
high temperature kills film immediately. Film stored in hot attic like an oven in summer, film will not survive. Never leave film in car during hot summer (exposed film even worse!). iI will scream like your dog in such case. Film need to be stored in cool place. There are different opinions how cool it should be, some sources says - froze films up to -24°C if you planing to store it for a long time. Other sources says that it will destroy gelatin on film surface and film should not be frozen but stored cool up to 5°C.
Who is right? I don't know. But I know, since you will get any old, expired vintage analog film - store it on cool place, fridge, 5-10°C will be fine for them.
another film killer. I don't collect films (or worse - papers) that looks like were flooded or have some traces of water effects, stains on film package are usually red alert or me. Also exposing on high humidity causing fungi and mold that you can smell. Obvious film killer.
From my experience, such "flooded" films, regardless exposing and developing method, always are too dark and without contrast, don't allow print anything looks even a bit okey. I think humidity causing galatine "melting" and silver bromide oxides "evaporates" from it.
Of course you can still do some artistic, funny and interesting prints on such film, basically based on exposing on very high contrasting places, but... it is too high for me.
Also - vice versa effect - humidity cannot be zero. Film stored in too dry place will... break. Not sure about emulsion contrast as never get such example, but obviously dried up film will break, for example inside the camera.
So, once you have your vintage old expired film, store it with humidity from about 55% to 65%, be careful about fridge with food! It has usually humidity much higher. Don't forgot to use some waterproof box if you want to store films in fridge together with foor or.... buy dedicated frigde like I did :)
time is inexorable. any film stored even in proper place, cool and dry, stored for dozen of years will lost some sensitiveness. rule says film is losing one step on ISO for each of 10 years. so, after 40 years, film with nominal value of 400 ISO will behave like ... 4 step less... so 400, 200, 100, 50, 25.. so, you should expose it like 25 ISO. read more about eV on next section, as this is just a rule and rules are to be broken.
All those 3 aspects causing something called "smoke". Negative is not black and transparent but whole grey, light grey, dark grey. Not exposed background of the negative looks like exposed. Looks not transparent but ... smoked.
Conclusion? 99/100 times you don't know how films has been stored and where. Unrepeatable experience and totally unknown results. This is what awaits you, So... amazing lottery!
Always good if you have a few films from the same source, stored together for years. You can use one to test based on Golden Rules (below) and then adjust process for the others, based on first results. This is what I'm doing for you. You can try my unique collection of vintage analog films from all of the world. Any single set were tested with camera, developed, copy printed in dark room and then process adjusted and explained.
What is a problem with expired analog film? - related content
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Step by step guide how I test analog vintage expired film (OWRO MA8 in this example). Every film in my collection is tested that way. check here for real life guide with examples.
Old analog film, expired years ago? Don't know how has been stored and where? What to do? How to expose it, how to develop it? READ MORE if you are you ready for unrepeatable experience and totally unknown results. Amazing lottery that can be predicted.
How to get working vintage analog film?
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