Abstract: The invention concerns a method for photopolymerizing a polymerisable coating applied on a substrate as well as an installation for implementing said method, enabling very high quality coatings to be obtained and polymerization time to be significantly reduced. Said method is essentially characterized in that it consists in performing at least two rapid simultaneous or successive exposures of the coating deposited on the substrate to infrared rays having different wavelengths derived from at least one generator of short infrared rays (22a) and from at least one generator of medium infrared rays (22b) arranged on the side of said substrate surface (23). The invention is useful for coating industrial and/or household objects made of wood, metal, synthetic or composite materials, or mixtures thereof or the like.