The purpose of the specifications for a U.S. Passport photo are to ensure a good likeness of the passport holder can be recorded on the passport. The requirement for a clear, white background, no headgear or sunglasses, and a neutral expression also allow biometric data to be recorded for security checks at airports.
U.S. passport photographs must be 2 inches by 2 inches square, excluding borders. A gap of half an inch must be left between the top of the head and the top of the photograph; and the head must take up between 1 inch and 1 3/8 of an inch of the height of the photograph. This ensures a standardized size of photograph with the face being the major feature.
Passport photos require a white background. The face is the primary feature of the photograph; which should show head and shoulders only. Because the purpose is to show a good representation of the passport holder, hats or other headgear, including sunglasses, must not be worn. Religious headgear may feature only if a signed statement attesting to its daily use for religious purposes accompanies the picture.
Photographs clear of background distractions or items covering the face allow for quicker comparison of the passport and the user, and more efficient biometric data; making security stronger and more efficient at the airport. This in turn also makes the use of passports for identification and travel purposes far quicker and easier.
The fact that the specifications are stringent has meant that many home photographs using digital cameras and webcams are no longer viable as passport photographs; nor are traditional school photographs, due to the stringent requirement for a neutral facial expression. As a result, the cost of applying for a passport can increase because the cost of photographs must also be factored in.
