Abstract: Substrate holders (16) having approximately plate-like, parallelepipedal configuration which can be moved in the vertical position along a given transport path through coating stations. The substrate holder (16) has frame-shaped sides parts (16a, 16b) disposed in parallel planes, in whose window-like openings (25, 26) the substrates (22, 23) are received. Wiping contacts (29, 29a and 30, 30a) are provided on stationary mountings (27, 28) and their resilient ends make contact with the electrically conductive coating (22a, 23a) upon movement through the station, and an electrical circuit can be closed briefly through these wiping contacts (29, 29a and 30, 30a) and the coating (22a, 23a), producing a heating and tempering of the material of the coating.