A light emitting diode-based skin cosmetic device includes a first light emitting panel, a second light emitting panel, a first narrow band filter, a second narrow band filter and an optical window. A reading device senses characteristic features of users who operate the machine. For each inter-rib space forming part of a group including at least three arbitrary and directly consecutive inter-rib spaces, a single access opening is provided on the side panels, the openings arranged alternately on the first and second side panels. The breather plate has one or more longitudinal grooves in a working surface. A data structure maintains a list of active edges for each slab, where an edge is active if the edge intersects any z plane in the slab. The impression medium includes a top layer and a backing layer disposed between the top layer and the impression member.