The maximum size of PDFs is, normally, several hundred kilometers on a side. But the developer Alex Chan managed, by modifying a few settings, to make a very, very very large PDF file.
Officially, the maximum size of a PDF is 381 x 381 km — an already enormous volume, which represents an area larger than Belgium, and equivalent to a third of Germany. However, developer Alex Chan wanted to see if she could further push the boundaries of the format. And the result is, literally, enormous.
In a post published on her blog on January 31, 2024, she says she managed to create an absolutely gigantic PDF: a document 37 trillion light years across, or a square of 1,369 trillion light years. ” VSis even bigger than the size of the universe ”, according to Alex Chan. The size of the observable universe is estimated at a sphere with a diameter of 93 billion light years.
How to make a huge PDF?
To succeed in her feat, the developer had to be cunning. The maximum size of a PDF is in fact specified in the PDF 1.6 user manual, available for download here. The document states that “ Acrobat 7.0 supports a maximum UserUnit value of 75,000, which gives a maximum page size of 15,000,000 inches “. 15 million inches being equal to 381 km, the theoretical limit size of a PDF is 381 km on each side, therefore 145,161 km².
However, by changing the size of some parameters, something larger can be achieved. Much, much bigger. Looking in the code of a PDF, Alex Chan realized that by changing the size of a parameter called MediaBox, it is entirely possible “ to enlarge the page. »
“ If you try to create a larger page size, by increasing the MediaBox or UserUnit values, Acrobat does not take this into account. It continues to say that the size of a page is 15 million inches, even though the page’s metadata indicates a larger size. But unlike Acrobat, the Preview application has no upper limit on what one can put in MediaBox. I can very well write a width which is a 1 followed by twelve 0s “, she writes. By changing a few parameters in the code, Alex Chan was able to create a monster.
By continuing to play with the settings, the developer obtained “ a PDF that Preview says is larger than the entire universe, about 37 trillion light years. » Definitely a unique PDF — and if you want it, Alex Chan has made it available publicly, on his site. As she recommends in her article, it’s best not to try to print it.
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