Validation of using a finger as support of a fingerprint may include: placing the support such that it bears; capturing a captured image of the print; transforming the captured image into a resulting image by passage through a low-pass filter; locating on the resulting image an origin point, the intensity of whose pixel is representative of the maximum pressure exerted on the support; verifying that, on the resulting image, for a plurality of radii issuing from the origin point, and for each of said radii, for a plurality of points M, the intensity of the pixel of each point M of said radius is representative of a decline in the pressure exerted on the support as the distance from the origin point to the point M increases, and a decision as regards the validity of the support is taken as a function of the results of the verification step.