1. A validation method, intended to validate the fact that an element is covered with a true skin and implemented by a validation device comprising a light source at at least one wavelength, a sensor, an analysis module and a decision-taking module, said validation method comprising: a positioning step during which a surface of said element is placed in front of the light source and the sensor; an illumination step during which the light source illuminates said element; a capture step for capturing, by means of said sensor, for the or each wavelength, an image of said element thus positioned that encompasses an illuminated zone of said element directly illuminated by the light beam emitted by the light source and a peripheral zone, referred to as the diffusion zone of said element, which is peripheral to said illuminated zone; an analysis step during which the or each image thus captured is analysed; and a decision-taking step during which the decision-taking module takes a decision as to whether said element is covered with a true skin according to the results of the analysis step.