The most beautiful invention of all time
March 3, 2025 5:31 PM Subscribe
Its design is a chef's kiss. It can scale from love note to embracing the world. And it united countries and continents in the aftermath of war. In this short SLYT, mathematician Hannah Fry explains why she adores A4.
Bonus Cats. In. Space.
Bonus Cats. In. Space.
All over the world people were driven insane by their printers telling them to “Load Letter” and wondering what on earth that could possibly mean.
It took me years to find out that Americans had this weird paper size called “Letter”.
posted by awfurby at 6:54 PM on March 3 [13 favorites]
It took me years to find out that Americans had this weird paper size called “Letter”.
posted by awfurby at 6:54 PM on March 3 [13 favorites]
I wonder if as part of Canada's moving away from the US we could switch our paper standard from Letter to A4 and related sizes.
posted by any portmanteau in a storm at 7:13 PM on March 3 [9 favorites]
posted by any portmanteau in a storm at 7:13 PM on March 3 [9 favorites]
I wonder if as part of Canada's moving away from the US we could switch our paper standard from Letter to A4 and related sizes.
Do it. Rekindle your metrication, even if just to spite your abusive neighbour!
posted by neonamber at 7:46 PM on March 3 [11 favorites]
Do it. Rekindle your metrication, even if just to spite your abusive neighbour!
posted by neonamber at 7:46 PM on March 3 [11 favorites]
CGP Grey put together a wonderful video on this same subject a few years ago. A delightful rabbit hole of a video, as he is wont to do.
posted by los pantalones del muerte at 8:10 PM on March 3 [4 favorites]
posted by los pantalones del muerte at 8:10 PM on March 3 [4 favorites]
Discovering the A and B series of paper was one of those fun surprises of living in Japan in the 90s…
posted by torokunai2 at 8:39 PM on March 3 [1 favorite]
posted by torokunai2 at 8:39 PM on March 3 [1 favorite]
But it misses the cool part: if you use the whole DIN/ISO drawing system with the recommended technical pen widths, the lines stay the right thickness when you optically magnify/reduce: a 0.5 mm pen on A2 reduces to 0.35 mm on A3, which reduces to 0.25 mm on A4. Magic.
Canada technically has PA4, a paper size I don't want to talk about. You might be able to find a dusty ream of it knocking about a couple of specialist stationer's in Ottawa or Gatineau, but nowhere else.
posted by scruss at 8:53 PM on March 3 [11 favorites]
Canada technically has PA4, a paper size I don't want to talk about. You might be able to find a dusty ream of it knocking about a couple of specialist stationer's in Ottawa or Gatineau, but nowhere else.
posted by scruss at 8:53 PM on March 3 [11 favorites]
As someone who has lived in the US since birth, I'd just like to say that it's a stupid country and I'm jealous of civilized places with systems that make sense.
posted by Ickster at 9:04 PM on March 3 [8 favorites]
posted by Ickster at 9:04 PM on March 3 [8 favorites]
↪ But it misses the cool part . . . 0.5 mm pen on A2 reduces to 0.35 mm on A3, which reduces to 0.25 mm on A4. Magic.
Not the only cool part:
Xerox paper is typically marketed as 80gsm (grams per square meter). Indeed this is the DIN 6730 [Deutsches Institut für Normung] Standard for Paper definition of a ream. A0 paper is defined as being 1sq.m. in size so a single sheet of A0 weights 80g. A1 is half the size of A0 in the same proportions and weighs 40g . . . A2 = 20g; A3 = 10g; A4 = 5g. A decimal ream is 500 sheets weighing in total 2500g. Which means that you can use paper to weigh anything from 5g to 25kg (a stack of 10 reams or two xerox-boxfuls).
And don't let me catch myself calling 480 sheets (20 quires of 24 sheets each) a ream. That is a 'short' ream which was put aside together with the fountain pens that used to spatter across it . . . along with a printer's ream [516 sheets]; a mill ream [472]; and a stationer's ream [504]. Life in the stationery world used to be more interesting but also more complicated.
posted by BobTheScientist at 10:55 PM on March 3 [17 favorites]
Not the only cool part:
Xerox paper is typically marketed as 80gsm (grams per square meter). Indeed this is the DIN 6730 [Deutsches Institut für Normung] Standard for Paper definition of a ream. A0 paper is defined as being 1sq.m. in size so a single sheet of A0 weights 80g. A1 is half the size of A0 in the same proportions and weighs 40g . . . A2 = 20g; A3 = 10g; A4 = 5g. A decimal ream is 500 sheets weighing in total 2500g. Which means that you can use paper to weigh anything from 5g to 25kg (a stack of 10 reams or two xerox-boxfuls).
And don't let me catch myself calling 480 sheets (20 quires of 24 sheets each) a ream. That is a 'short' ream which was put aside together with the fountain pens that used to spatter across it . . . along with a printer's ream [516 sheets]; a mill ream [472]; and a stationer's ream [504]. Life in the stationery world used to be more interesting but also more complicated.
posted by BobTheScientist at 10:55 PM on March 3 [17 favorites]
There's definitely an elegance to the theoretical scalability of ISO paper sizes, and I am partial to the portability of the A5-size notebook. It's also nifty that paper weight, in terms of grams per square meter, is easily transferable to whatever size sheet you're using (90g paper = 5.625 g per A4 sheet, pardon my abuse of significant digits). It's also super irritating that many software programs default to letter-size, and I've even had difficulty dealing with the US bureaucracy in the past when submitting forms printed on A4, to the point that I, sitting here in Sweden, have a folder of 8.5x11" blank paper in reserve just for printing US government forms.
But, hear me out, using irrational numbers for standardized units is rather unfortunate. My friends are all design nerds so of course they know that an A4 is 210x297mm, but this is not knowledge I imagine your average everyday European walks around knowing in their head. All the metric-system apologists here will rag endlessly on the fact that a mile is 5280 feet, but can somehow forgive a unit paper size everyone deals with daily having a length of 297mm. Also: hewing to the even millimeter standard of ISO exposes the lie of a consistent aspect ratio. 16 A4 sheets provide "square meter" dimensions shy of the official A0 paper (and suddenly the approximation of A4 paper weight in milligrams above is exposed as problematic) of 841x1189mm.
posted by St. Oops at 11:03 PM on March 3 [7 favorites]
But, hear me out, using irrational numbers for standardized units is rather unfortunate. My friends are all design nerds so of course they know that an A4 is 210x297mm, but this is not knowledge I imagine your average everyday European walks around knowing in their head. All the metric-system apologists here will rag endlessly on the fact that a mile is 5280 feet, but can somehow forgive a unit paper size everyone deals with daily having a length of 297mm. Also: hewing to the even millimeter standard of ISO exposes the lie of a consistent aspect ratio. 16 A4 sheets provide "square meter" dimensions shy of the official A0 paper (and suddenly the approximation of A4 paper weight in milligrams above is exposed as problematic) of 841x1189mm.
posted by St. Oops at 11:03 PM on March 3 [7 favorites]
A4 is wonderful, but A5 fills my heart with joy. And there's something really magical about A1 posters, just the right amount of cinematic splendor.
posted by Jra at 11:23 PM on March 3 [2 favorites]
posted by Jra at 11:23 PM on March 3 [2 favorites]
Flashbacks to 'US Load Letter' on the old printers well stocked with A4. All it took to hold up everyone elses printing was an incorrectly set default paper size. Pre-internet it was wild to me that different paper sizes existed in the world (and they weren't even remotely metric).
posted by phigmov at 11:29 PM on March 3 [3 favorites]
posted by phigmov at 11:29 PM on March 3 [3 favorites]
From the Japan end of things, there are also so many nifty notebook holders, satchels and backpacks made to fit A4. So many! Whenever I’m waiting for someone, I find a stationer or a luggage store and window shop.
posted by Ice Cream Socialist at 12:59 AM on March 4 [3 favorites]
posted by Ice Cream Socialist at 12:59 AM on March 4 [3 favorites]
It took me years to find out that Americans had this weird paper size called “Letter”.
Oh come on, that's just eight and a half by eleven!
That is a 'short' ream which was put aside together with the fountain pens that used to spatter across it . . . along with a printer's ream [516 sheets]; a mill ream [472]; and a stationer's ream [504].
Sir, this is a Wendy's
posted by chavenet at 1:34 AM on March 4 [4 favorites]
Oh come on, that's just eight and a half by eleven!
That is a 'short' ream which was put aside together with the fountain pens that used to spatter across it . . . along with a printer's ream [516 sheets]; a mill ream [472]; and a stationer's ream [504].
Sir, this is a Wendy's
posted by chavenet at 1:34 AM on March 4 [4 favorites]
As a child in school we were handed individual sheets of foolscap paper (8.5in x 13.5in) to write on. The 70s were such a whirl of brand new cool stuff that A&B size papers just appeared and were part of the new world. After becoming accustomed to that, experiencing Letter size for the first time was rather a shock.
My first few years of computing were largely with British computers and software, so apart from line-printer paper, which came in big (initially) and then little, I was spared the letter size nonsense until I had to use American operating systems and sheet feed printers (I miss daisy wheel printers, computing used to have such fun toys).
posted by epo at 3:26 AM on March 4
My first few years of computing were largely with British computers and software, so apart from line-printer paper, which came in big (initially) and then little, I was spared the letter size nonsense until I had to use American operating systems and sheet feed printers (I miss daisy wheel printers, computing used to have such fun toys).
posted by epo at 3:26 AM on March 4
I have discovered that the ideal notebook size for me is B6, but I will abide an A5 in a pinch.
posted by rum-soaked space hobo at 3:50 AM on March 4
posted by rum-soaked space hobo at 3:50 AM on March 4
Oh come on, that's just eight and a half by eleven!
Eight and a half by eleven whats?!
posted by Literaryhero at 4:24 AM on March 4
Eight and a half by eleven whats?!
posted by Literaryhero at 4:24 AM on March 4
Units!
posted by chavenet at 4:42 AM on March 4 [2 favorites]
posted by chavenet at 4:42 AM on March 4 [2 favorites]
Having been spoiled by the standarization of the wonderous A0 all my life I have something of a kink for non-standard sizes. My most cherished purchase when I went to NY a while back was a box of generic Staples envelopes (6x9" maybe?) with that little clasp thingy. Kept it for my most premium recipients of post.
Going to Japan this spring and look forwards to browsing stationary stores – is it worthwhile to get store recommendations or is Tokyo/Osaka abundent with choice?
A curiou: Sweden has a non-standard hole-punch system: Trio-punching.
posted by monocultured at 5:21 AM on March 4 [1 favorite]
Going to Japan this spring and look forwards to browsing stationary stores – is it worthwhile to get store recommendations or is Tokyo/Osaka abundent with choice?
A curiou: Sweden has a non-standard hole-punch system: Trio-punching.
posted by monocultured at 5:21 AM on March 4 [1 favorite]
Haha you have better paper standards than us savages in the US but your TRIO punch system uses four holes! Does look cool though :)
posted by SaltySalticid at 5:44 AM on March 4 [1 favorite]
posted by SaltySalticid at 5:44 AM on March 4 [1 favorite]
→
Uh, that's gsm not being broken, doing what it should. It's US paper weights that are bananapants: card stock and printer paper use different base weights in the American system. They both say pounds, but it's pounds for a different amount of stuff. Wibble.
I've realized it's a lot easier to stop worrying about the derivation of any US customary unit (or by unfortunate extension, any current US policy). I am much more at peace by knowing that the reason (to be blunt) is because fuck you, that's why! Odd paper sizes? Fuck you! Odd paper weights? Fuck you! Myriad screw threads? Fuck you!
You see? It's really quite liberating.
Back to A4: if you're in Canada, and near one of the few Oomomo stores, they have A4 paper and folders. It might be a little expensive for me to fill That Brother Printer with A4 just for badness, but everything just got 25% more expensive here.
posted by scruss at 8:46 AM on March 4 [2 favorites]
Not the only cool part: Xerox paper is typically marketed as 80gsm (grams per square meter).
Uh, that's gsm not being broken, doing what it should. It's US paper weights that are bananapants: card stock and printer paper use different base weights in the American system. They both say pounds, but it's pounds for a different amount of stuff. Wibble.
I've realized it's a lot easier to stop worrying about the derivation of any US customary unit (or by unfortunate extension, any current US policy). I am much more at peace by knowing that the reason (to be blunt) is because fuck you, that's why! Odd paper sizes? Fuck you! Odd paper weights? Fuck you! Myriad screw threads? Fuck you!
You see? It's really quite liberating.
Back to A4: if you're in Canada, and near one of the few Oomomo stores, they have A4 paper and folders. It might be a little expensive for me to fill That Brother Printer with A4 just for badness, but everything just got 25% more expensive here.
posted by scruss at 8:46 AM on March 4 [2 favorites]
@monocultured: Loft stores have lovely stationery sections, but you have to go to Itoya in Ginza, and Traveler's Company has a tiny store in Tokyo Station right in front of the shinkansen gates with items you can only get there (other stores have different limited items, but these are my faves).
posted by sukeban at 8:48 AM on March 4 [4 favorites]
posted by sukeban at 8:48 AM on March 4 [4 favorites]
I used to run a digital print shop, and ISO paper sizes are just so much better. Everything scales perfectly. I always tried to get our clients to design in ISO sizes so they could scale their A4 flyer to an A3 or A2 poster easily, but nope. Letter/Ledger is just too ingrained. I did keep a supply of ISO paper on-hand, for our more sensible clients, but also because we're a port town and we'd frequently have ship crews that needed stuff printed, and they were always amazed that we had A5/A4/A3 paper, punches, and ring binders just ready to go.
I trained our staff to think of paper weights in terms of gsm. Because, invariably, you'd get a customer saying "Print it on 90 pound." Okay, 90 pound what?
posted by xedrik at 9:26 AM on March 4 [1 favorite]
I trained our staff to think of paper weights in terms of gsm. Because, invariably, you'd get a customer saying "Print it on 90 pound." Okay, 90 pound what?
posted by xedrik at 9:26 AM on March 4 [1 favorite]
I thought paper was obsolete. The whole 21st century thing. AI does not need paper, why do you?
posted by JohnnyGunn at 11:53 AM on March 4 [1 favorite]
posted by JohnnyGunn at 11:53 AM on March 4 [1 favorite]
I also love A4 and all the related paper sizes. I first started using actual stationery at a time when (in Australia) there was still both Foolscap and Letter size paper in use as well as the proper sizes and it was a pain in the arse, especially in a world of printers that were dumb enough to just print whatever you sent on whatever paper some idiot had put in there. So you either had to guillotine off the extra bits of paper in the bottom or re-print all your pages that ran off the bottom of the page. It's a shame that universal use of A4 etc became reality at about the same time we started to wean ourselves off paper at all. I miss all stationery, but A4 paper most of all :-(
posted by dg at 2:54 PM on March 4
posted by dg at 2:54 PM on March 4
(Whispering) I encounter this paper-measurement standard not-infrequently, and I still struggle to remember whether the paper gets bigger or smaller as the numbers get bigger or smaller.
posted by TangoCharlie at 8:22 AM on March 5
posted by TangoCharlie at 8:22 AM on March 5
Just think of the number sort of like a denominator. The number is how many times it's been halved, and you start at zero because everyone loves that the biggest size has be halved zero times.
Formally, AN paper has an area of 1/(2^N) m^2 paper.
posted by SaltySalticid at 8:45 AM on March 5
Formally, AN paper has an area of 1/(2^N) m^2 paper.
posted by SaltySalticid at 8:45 AM on March 5
I'm not a huge fan of metric to begin with, but damn if metric paper sizes don't make fuckin' sense.
posted by grubi at 8:53 AM on March 5
posted by grubi at 8:53 AM on March 5
I have a serious soft spot for A4 paper. I took my last semester of undergrad in England and after using a computer and printing my essays out, I was to a land of A4 paper and was only permitted to hand write the two 6 to 8 page essays each week (if not more). I found I really enjoyed writing on A4 ruled paper (the lines were closer together than "college ruled" which there was no standard for).
When I got back to the US I kept getting jobs where A4 paper was needed on occasion for submissions for things international. I knew the office supply companies that carried it or could easily deliver a ream or case. After grad school in DC my second job needed it for papers being handed to international regulatory bodies, but finding A4 in DC was a pain. I'd end up trading with the Canadian Embassy or the Organization of American States 2 reams of legal size for one ream of A4.
For personal notes I got hooked on Rhodia purple grid pads in A4 when in England (thanks to a friend in France who came to visit).
posted by vanderwal at 10:16 AM on March 5
When I got back to the US I kept getting jobs where A4 paper was needed on occasion for submissions for things international. I knew the office supply companies that carried it or could easily deliver a ream or case. After grad school in DC my second job needed it for papers being handed to international regulatory bodies, but finding A4 in DC was a pain. I'd end up trading with the Canadian Embassy or the Organization of American States 2 reams of legal size for one ream of A4.
For personal notes I got hooked on Rhodia purple grid pads in A4 when in England (thanks to a friend in France who came to visit).
posted by vanderwal at 10:16 AM on March 5
Mod note: The greatest invention ever? Ok, fine, we'll add it to the sidebar and Best Of blog!
posted by Brandon Blatcher (staff) at 3:16 PM on March 5 [1 favorite]
posted by Brandon Blatcher (staff) at 3:16 PM on March 5 [1 favorite]
I remember Martin Gardner writing that the golden rectangle was intrinsically more pleasing than other rectangles to the human eye, and that humans could detect smaller deviations from it than from any other rectangle.
The golden rectangle’s ratio of long side to short is ~1.618; A4's side ratio is ~1.414; and 11/8.5 = ~1.294.
posted by jamjam at 3:44 PM on March 5 [2 favorites]
The golden rectangle’s ratio of long side to short is ~1.618; A4's side ratio is ~1.414; and 11/8.5 = ~1.294.
posted by jamjam at 3:44 PM on March 5 [2 favorites]
Standard playing cards are 3.5" X 2.5", which is a ratio of 1.4, and therefore within about 1% of A4.
posted by jamjam at 12:54 PM on March 6
posted by jamjam at 12:54 PM on March 6
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