Canon selphy cp1500 privacy concerns

2 points by azca 321 days ago | 4 comments

Noticed today while throwing out a cartridge that the dye sublimation used leaves the negatives in each color (blue, yellow, magenta, white) for each photo and the details are enough to reconstruct the pictures if someone spent a little time to automate via Photoshop or gimp to layer and merge the inverse of each color. Searching for this on Google didn't seem to produce any relevant results so I figured I'd post here to be corrected on my assumptions, or at least raise awareness that it's a concern. Canon publishes quite a bit of support docs around privacy for the digital usage side of devices, but I guess old school exfiltrarion is still a possibility.

Anyone at Canon or relevant industries have any insight? What's a proper and privacy friendly consumer disposal option for these cartridges?

brudgers 321 days ago |

If people are picking through your trash to reconstruct images from selphy cartridges and that matters, you probably have bigger operational security issues.

Because that takes a rather determined adversary with non-trivial resources, you probably should avoid doing the things that attract such an adversary.

azca 320 days ago | |

Thank you for your reply. I wasn't looking for an op sec answer but more of a technical concern around design of the product - i.e why didn't they think of it, or if they did what made them not solve the problem with other tech solutions (dummy prints, zero out, patterns, or even a thermal or physical recycle program). At least communicate this is possible like they addressed the digital safety side of it.

I don't believe it would take too much lift to automate this with a scanner+some software.

aag01 321 days ago |

This occurs on almost every dye sublimation printer that uses those disposable cartridges. I recall seeing this on a Sony printer from the mid 90s. It's not specific to canon.

azca 320 days ago | |

Thank you. I wonder if they considered a dummy cycle on a relevant media type after the print to zero out what's left over. Specially if some other patterns could be introduced to randomize what's left.