Back of the envelope on storage capacity:
- Looks like about 200x200 px grid
- 200x200 = 40,000 total possible bits
- Assume only 75% of these are available for data due to QR structure and redundancy features
- Leaves about 30,000 bits or 3-4 kb capacity in that one image
- Comes out to about 5 reams of paper per mb of data storage<p>This would be a better "ping pong balls on a plane" interview question for comp sci candidates.
While I'm neither an expert in data backup or an archivist I'm willing to guess that it would highly recommended that anyone using a method such as this to use high quality acid-free archival grade paper to avoid the inevitable ink fade that occurs with lower quality paper types.
I had this exact idea a few years ago.<p>It was a neat idea, to offline your data to analog format. But, it would require a lot of paper printouts to back up your data.<p>The paper printout might actually last longer than CDROMs.<p>A more interesting idea, would be to encrypt your data, and back it up to the cloud. Then, the printout is just the password-protected key to re-download the data, and decrypt it.