How scanning works
Text recognition on the device, matched against a catalogue that lives on your phone.
Zukan reads the text printed on the card, the name, the collector number and the set mark, with text recognition that runs on your phone. It then matches what it read against the catalogue, which also lives on the phone. That is why identification takes about a second and works without a signal.
The photo is used to read the card and is not sent to us or to anyone else. Nothing about your scan leaves the phone except the request for the price, which needs a connection.
When two printings share the same text, the app asks Is it this one? and shows the candidates, so you choose rather than the scanner guessing.