How long can used film be kept before it is developed?

On the Shelf Life of Unused Film

Let’s let the cat out of the bag - or the Maine Coon out of the carrier bag, to be more precise. (That’s a joke for you, Alfie fans). As many of you might know, I am an avid film photographer, an obscurity in this age of pixel peeping digital photography that my ever-suffering wife, Niamh, often recollects fondly when she can't find her phone charger. Anyway, let's dive into the world of film photography.

So, the burning question of the day for all the analogue aficionados out there is, how long can used film keep before you develop it? It's like asking how long a piece of string is or how much patience Niamh has for my photography hobby. They’re both likely answered by 'Well, it depends'.

The Science Behind Film Degradation

Understanding how long used film can be kept before developing requires the basics of the chemistry involved. Film is essentially a photosensitive strip coated with a gelatin emulsion containing silver halides. These little silver halide buddies are what react to light and capture the image. When the film is exposed to light, it forms a latent image, soft-spoken and shy, waiting for chemical developers to bring it to life.

Thing is, these silver halides aren't exactly the most patient bunch. They're much like my youngest, Elspeth, on a rainy day when she can't go play outside - restless. Even without light, they can slowly react over time, leading to what we call 'fogging'. Fogged film results in lower contrast and muddier shadows and all around a grumpier photographer. Me, in this case.

Stability of The Magical Latent Image

The stability of the latent image over time is largely dependent on a few factors, with film type (color or black and white), storage conditions, and the rate of fogging taking center stage. Black and white film enjoys a longer shelf life, much like my mother's infamous plum pudding that still tasted wonderful warmed up days after Christmas.

Essentially, cooler and drier storage conditions slow down the fogging process in both used and unused film. In the same way you wouldn't store Niamh's homemade cookies above the radiator (if you value your life and your sweet treat), storing film at room temperature or above can accelerate its degradation. So, find yourself a cool, dry and dark place. Much like that small corner in the attic where Fergus hides when it's his turn to do the dishes.

The Crucial Storage Hacks

Now, this is where I’ll let you in on a few of my top storage hacks for film. This has saved me time and again, ensuring I never lose any of the family's precious memories, with the exception of that one time on our summer trip when Alfie decided to use my film as a plaything.

Wrap your used film in foil, then place it in a sealed plastic bag before tossing it in the fridge (or freezer if you won't need it for a while). Much like Niamh’s lasagna, film keeps best when it’s cold. Also, I cannot emphasize enough, label your film. There is nothing more disorienting than opening a roll of film only to discover it’s time-lapsed photos of Fergus’s science project instead of Elspeth’s birthday party.

Timings, And Some Personal Anecdotes

So, after all this rambling, you just want the skinny, number crunching part, don't you? Well, general wisdom advises that used film should be developed soon after exposure. It's best within a month, but with good storage, you could stretch this up to a year. Remember, the sooner, the better. It's like cleaning the litter box after Alfie is done with his business; procrastination doesn’t make it any easier.

I once found a forgotten roll of Kodachrome in my dad's old Pentax that had been languishing for over 30 years. Out of sheer curiosity, I decided to develop it anyway. To my astonishment, there were still images! Granted, the colors had faded a little and the contrast was not as pronounced, but the memories were still vivid and heart-stirring. It turned out to be frozen fragments of my parents' honeymoon, a visual legacy that I, and my brother Jack, will cherish forever.

In case you're wondering, the longest film I've personally stored before developing was an Ilford HP5 roll that sat on the shelf (cringe) for nearly two years. That roll yielded photographs from Fergus' first day of school, Elspeth dancing in her first recital and multiple portraits of a younger, less mottled Alfie. They were far from technically perfect, but as charming and cherished as Niamh’s first batch of homemade scones.

So, there you have it, a comprehensive, albeit long-winded, examination of used film shelf life. Store it like you're hoarding Niamh's cookies for the apocalypse, get developing as soon as you can, and remember to always infuse a good dose of humor and love into your shooting sessions. Till then, stay out of the fog. Makes you look all ghostly, says Alfie.