Using printed QR codes for links in books

16.55, Tuesday 12 Jan 2021

I’m currently reading Alexandra Deschamps-Sonsino’s excellent Creating a Culture of Innovation, which is simultaneously a survey, history, and playbook for how to invent the future from inside corporations.

(Cleverly, Alex is serialising the book as a series of free Friday lectures, starting later this month. Register for tickets here.)

There are many links in the footnotes, which is great. But I like reading on paper (it helps me focus) and it is tedious typing URLs into my phone browser letter by letter.

We had a similar problem with Mind Hacks, and our workaround then was to put all the links on a single web page. Functional but not great.

So I was very taken with Tom Critchlow’s recent experiments with printed QR codes (for his upcoming book on indie consultancy):

Is there an “in-line” QR code format? The print book <–> HTML connection is awful. Best standard seems to be footnote the link and then print the URL…

He shows a couple of elegant examples of what he’s looking for, such as

QR codes are a neat solution because smartphone cameras natively resolve them to hyperlinks, without even taking a photo.


As this deep dive into printed QR codes shows, there are design challenges:

  • Web addresses are long, which makes QR codes bigger
  • The codes can’t be shrunk because they bump up against print resolution limits (and, I’ve found, because smartphone cameras can’t focus on anything too small and too close).

So, taking this route, you end up with large QR codes on the page. Not ideal. At worst, ugly.

Of course there are workarounds: one big QR code per chapter, perhaps, providing a menu of all the links in all the footnotes.

I’d love to see a solution like Critchlow’s original mockups. Inline, robot-readable links have an elegance that reminds me of Tufte’s sparklines. Though perhaps this route has reached a dead end.

What’s the limit on how small a QR code can be printed - and scanned reliably - and what’s the character limit for that? Could it contain a URL?

Is there an alternative QR code standard which is simultaneously much more compact, and also already supported by smartphone cameras?

If we need a whole new standard, we could think about sorting out the opaqueness problem of existing QR codes. What about a robot-readable glyph that was interpreted by the smartphone camera to simply mean: use OCR on the following string of characters and treat it as a web address (or a bank account number, or a Twitter username, or whatever). Basically a robot-readable protocol prefix, like “http:”. That would have the benefit of being robot-readable and human-readable simultaneously.

But new standards would take years. I’d prefer tiny QR codes in books that work today.

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