Why you are not allowed to smile in passports

Passport photo requirements vary by country, but generally, the guidelines are designed to ensure that the photo can be easily recognized as the person presenting the passport, and to prevent fraud and identity theft. In many cases, this means that the photo must show the person's face clearly and without obstruction, and that certain facial expressions, including smiling, may be prohibited. When a person smiles, their facial features can shift, and their teeth may be exposed, which can make it difficult for facial recognition software to match the photo to the person presenting the passport. Additionally, smiling can cause wrinkles and creases around the eyes and mouth, which can further obscure the person's features and make it more difficult to identify them. For these reasons, many passport photo guidelines specify that the person should maintain a neutral expression, with their mouth closed and their eyes open and facing forward. While this may seem inconvenient or unflattering, it is a necessary step to ensure the security and integrity of passport identification.