Method and apparatus for placing identification of a patient or other object on an x-ray picture produced on a dielectric receptor sheet by electron radiography. A system for providing a uniform charge on an identification zone of a dielectric receptor, and for discharging selected portions of the charged zone by contact with a photoconductor unit having selected portions thereof made conductive by radiation, with the selected portions providing the identification of the object. A roller mechanism and a flat plate mechanism for providing the contact between charged receptor and photoconductor unit. An optical system and a light emitting diode system for generating the identification pattern.