mounted pressure exerting roll 1 made from hard rubber with a hardness of 70 90 shore a counter pressure roll 3 made from metal with a shore hardness greater than that of pressure exerting roll 1 starting from the right hand side of the figure an electroformed screen 5 is supplied from above comprising a network of dykes 6 which delimit openings 7 at the same time an assembly comprising a polyester film 10 and a resist layer 13 composed of a first resist layer 15 and an additional resist layer 17 is supplied from the right hand side beneath the screen 5 the screen 5 is pressed into the resist layer 13 between the pressure exerting roll 1 and the counter pressure roll 3 during this process the screen 5 penetrates through the additional resist layer 17 and partially into the first resist layer 15 in this way a base material 25 according to the invention is obtained on the left hand side of rolls 1 and 3 this base material 25 having the following characteristics the distance d from the screen to the surface of the resist layer 13 on the side of the protective film 10 is uniform the distance d to clarify is represented as the distance between the surface 18 of the resist layer 13 on the side of the film 10 on the one hand and the tangent plane 19 of the dykes of the screen 5 on the side which projects into the resist layer 13 on the other hand the height h of the resist layer 13 is also uniform between the dykes 6 for.