Right. There’s no such thing as “120mm” film. The format is called just “120”!
I’m writing this post as part of a concerted effort to correct this bizarre misconception that seems to have taken over the internet. It’s most prevalent on Instagram where there are whole accounts dedicated to “120mm” and the hashtags #120mm and #120mmfilm have been used hundreds of thousands of times.
What’s worse are the online shops that have started calling the film 120mm in their shop listings – either through gross ignorance, or some attempt to optimise their websites for people searching the internet for this non-existent film format.
Let me repeat. There is no such thing as “120mm” film – not by designation at least – it is simply called “120”.
120 – the Kodak nomenclature
Ok, so why is it called “120” then? It’s quite simple – that’s what Kodak called it! Back in the early days of film, there were lots of different formats for lots of different cameras. As far as I can work out, in a bid to make things easier to understand, in the very early 20th century, Kodak started naming their films with numbers. 2 1/4” roll film was given the name “120”.
If you’re interested in reading more, there is a very informative Wikipedia article that details all the information here
Where do the misconceptions come from?
I have been baffled by this addition of “mm” to the 120 designation for a while, and have long wondered where it came from. I’ve long guessed that it originated from someone – or one might assume a lot of people – taking the “mm” off the end of “35mm” and adding it to 120. An easy mistake to make, perhaps, though it doesn’t make much sense in practice.
35mm film – which Kodak named “135” – is in fact 35mm wide. 120 film is about 61mm wide. 135 film has sprocket holes which take up the edge, so the part of the film that is exposed is actually on 24mm wide. About 56mm of 120 film is exposed to the light.
With both films, the other dimension of the exposure varies depending on the camera. 135 cameras range from 24x18mm to 24x65mm with 24x36mm being by far the most common format.
120 (medium format) cameras are a little different as there are lots of different formats with none of them being the “standard” format. In more modern times, the various 120 or “medium formats” are based on rounded numbers.
As an example, there are 645 cameras – the name 645 comes from a rounded size of exposure they take. They take 120 film, and the actual exposed part of the film is about 56mm x 41.5mm, but to keep things simple those millimetre measurements are rounded-up to 6cm x 4.5cm which in turn gives the 645 naming convention.
The same goes for 66, 67, 68, 69, 612 and 617 cameras. A 69 camera takes photos that are a little bit smaller than 6x9cm.
As you can see, the only medium format film format that has anything to do with 120mm is 612 – a format that is slightly less than 120mm on the long edge. But, this is far from the standard – the wider 612 and 617 formats are a lot less common than 645-69 formats. As such, there is no reason that 120 film would take its name from that wider format.
I also read the other day that some people think that 120 comes from the fact that 120 is 60 x 2 – i.e. the 66 format is where the name originated. With the rounding of numbers, I suppose it’s reasonably logical that this might be the case, but if you look at the chart on Wikipedia, there is no evidence of this system anywhere else, and in fact, it would appear it was just the 20th format to be given a name under the Kodak system of nomenclature. Additionally, as stated, 66 is no more standard than any other format.
So yeah, to repeat myself again, the format is called 120, and not 120mm as the latter doesn’t make much sense at all.
Does it really matter?
Of course, in reality, it doesn’t really matter… When people say 120mm, those of us who know they are misnaming it, also know they mean 120.
It’s just, well, why add the “mm” to the end? Why make it more confusing? Why sully the Kodak nomenclature that’s been around for 118 years? Calling is 120mm isn’t really hurting anyone, it’s just a bit stupid!
So what can we do to correct it?
If you find yourself rolling your eyes at all this 120mm nonsense, why not join me and EMULSIVE in trying to correct it? Here are some resources for you to use:
A website we’ve made – 120not120mm.com
A rant on EMULSIVE – emulsive.org/articles/rants/rants-theres-no-such-thing-as-120mm-film
The film format article on Wikipedia – en.wikipedia.org/wiki/Film_format
Twitter – @120NOT120MM
Instagram – @120_not_120mm
Facebook group – 120not120mm
Wherever you see this heinous misdemeanour, why not link to one of the above – you can even use the hashtag #120not120mm to help hammer the message home!
All of this will start spreading the word to all these people and accounts who are habitually compounding this nonsense!
Is it too late, has social media spread this post-truth nonsense too far and wide? Are there more important issues in the world that you could spend your time and efforts on? Probably, but I just can’t help facepalming every time I see #120mmfilm, and frankly, my forehead is starting to hurt…
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