Glasses, smiling and head coverings

The rules about what appears on your face are the ones people ask about most, and the ones written most vaguely. The underlying principle is consistent everywhere: the photo must show your face as it normally looks, fully visible from the bottom of the chin to the top of the forehead, with nothing obscuring the features a person or a machine would compare you against.

Glasses: take them off

Many authorities have moved from “no glare, no tinted lenses, frames must not cover the eyes” to simply not allowing glasses. Korea's foreign ministry requires photos without glasses. Where they are still permitted, the failure modes are unforgiving: a reflection on the lens, a heavy frame crossing the eye, or a slight tint that dims the iris. Since removing them costs nothing and no country requires you to wear glasses, take them off. The one exception is a medical dressing or eye patch you cannot remove, which usually needs a note from a doctor with the application.

Expression: neutral, mouth closed, eyes open

Every standard asks for a neutral expression with the mouth closed and both eyes open and clearly visible. A closed-lip half-smile usually passes; teeth do not. The reason is biometric rather than bureaucratic — face matching compares distances between fixed points, and a smile moves several of them. ID Photo measures the gap between the lips and how open the eyes are and warns before you print, which catches the half-blink that is genuinely hard to see on a phone.

Head coverings worn every day

A head covering worn daily for religious or medical reasons is generally accepted, on the condition that the full face is visible from the bottom of the chin to the top of the forehead, with no shadow cast across the features and no fabric crossing the face. Wide or wrapped styles that shade the eyes or jaw are what cause the trouble, not the covering itself. Requirements are set per country, so check the authority's own page — and note that if the covering hides the top of your head, the chin-to-crown measurement is taken to the top of the head as covered, which changes the crop.

Hair, and where the top of the head is

Head height is measured to the crown — the top of the skull including hair. Tall, voluminous or piled-up hair genuinely raises that point and can push the head out of range on a day it would otherwise pass. Wear your hair as you normally do, but if it stands well above your head, expect the face to sit lower in the frame. ID Photo detects the crown from the image and tells you when it had to estimate it or when hair made it ambiguous — an estimate is a warning rather than a pass, because the whole measurement rests on that point.