Method for forming a 3D image (IGF), from a lenticular structure comprising: - a support layer on which an arrangement of subpixels of at least two distinct colours (C1, C2, C3) is formed, each subpixel having a single colour among said at least two distinct colours; and - a lenticular array comprising convergent lenses arranged opposite the subpixel arrangement; the method comprising: a) visual inspection (S4) of the lenticular structure, by means of a camera , said visual inspection comprising the following steps for each of M distinct directions of observation (DR) relative to the lenticular array, M being an integer equal to at least 2: a1) positioning (S6) the camera according to the direction of observation (DR); a2) detecting (S8) subpixels that can be viewed through the lenses according to said direction of observation; b) determining (S10), from the colour of the subpixels detected in a2) for each direction of observation, grey levels to be generated to reveal, from the arrangement of subpixels, M images (IGX) viewable through the lenticular array according to the M directions of observation respectively; and c) personalising (S12) the arrangement of subpixels during which the grey levels determined in b) are etched opposite the subpixels in the support layer by focusing a laser radiation (RY1) through the lenticular array so as to reveal, from the subpixel arrangement combined with the grey levels, the M images (IGX) viewable through the lenticular array according to the M observation directions respectively, said M images collectively forming the 3D image (IGF). - a support layer on which an arrangement of subpixels of at least two distinct colours (C1, C2, C3) is formed, each subpixel having a single colour among said at least two distinct colours; and - a lenticular array comprising convergent lenses arranged opposite the subpixel arrangement; a) visual inspection (S4) of the lenticular structure, by means of a camera , said visual inspection comprising the following steps for each of M distinct directions of observation (DR) relative to the lenticular array, M being an integer equal to at least 2: a1) positioning (S6) the camera according to the direction of observation (DR); a2) detecting (S8) subpixels that can be viewed through the lenses according to said direction of observation; a1) positioning (S6) the camera according to the direction of observation (DR); a2) detecting (S8) subpixels that can be viewed through the lenses according to said direction of observation; b) determining (S10), from the colour of the subpixels detected in a2) for each direction of observation, grey levels to be generated to reveal, from the arrangement of subpixels, M images (IGX) viewable through the lenticular array according to the M directions of observation respectively; and c) personalising (S12) the arrangement of subpixels during which the grey levels determined in b) are etched opposite the subpixels in the support layer by focusing a laser radiation (RY1) through the lenticular array so as to reveal, from the subpixel arrangement combined with the grey levels, the M images (IGX) viewable through the lenticular array according to the M observation directions respectively, said M images collectively forming the 3D image (IGF). <EOS>