In all contemporary societies, photo-identity documents are used routinely for person identification, but this process is surprisingly fallible. Here we show that this problem is not limited to the identification of specific photographs of a person, but transcends three identity cards of the same person with different images. These identity cards varied substantially from each other in how well they could be recognised but identification rates were generally poor. We also present a potential solution to this problem by demonstrating that person identification can be improved when several photographs of the same person are made available.