Abstract: A biometric security procedure for manufacturing an identity document, such as an identity card, credit card, visa or passport, which includes the steps of: providing a nucleus of the identity document, the nucleus including personal data of a holder of the identity document and a face image of the holder; carrying out, by a computer and an image capturer such as a scanner or a video camera, an analysis of face features of the face image, the computer carrying out an analysis of basic face features of the face image, comparing the basic face features with master/pattern features in a data base, wherein each master/pattern feature has a specific number; obtaining by the analysis a derived set of master/pattern features that corresponds to a characteristic synthetic image of the holder, the derived set of master/pattern features corresponding to a specific numeric code determined by the number of each of the master/pattern features making up the derived set of master/pattern features; and printing the specific