I was curious, so I looked it up and it seems that around 3KB is the max for a single 177x177 code (though I imagine this is a “soft” limit?). With 600DPI being common for laser printers, a DPI-limited 3KB would be well under 1cm x 1cm. My hunch is that this wouldn’t be super reliable (DPI limit not necessarily the resolution of the printer?), but I’d be curious to see what the usable QR density actually is. But yeah…a few QR codes should do the trick!
also QR codes have EXTREME data redundancy, you can cover like half of a QR code and it’ll still work.
In our scenario we don’t need much redundancy, since the paper will be in controlled conditions and shouldn’t degrade, and we’ll make damn sure to scan the entire thing without crap obscuring it.
We also don’t need all the tracking features, all we need is a marking in one corner so we know what way to put it into the scanner.
All this taken together should result in a data density that is actually realistically useful with just one side of a single A4 sheet.
Imagine storing a digital photo on a piece of paper, and needing to scan it to reproduce the photo… someone needs to do this!
- Take picture with digital camera.
- Store as jpg
- Convert jpeg to base64 string
- Compress the string in a .zip split into 2.5KB chunks
- Encode the .zips as a base64 strings
- Render a QR code for each string.
- Print out all QR codes on a sheet
- Store in family photo album.
Most of that could be like 10 lines of python…
