12.—(1) The illumination of the roundel must be in accordance with this paragraph.
(2) The parts of the roundel coloured black must not be illuminated by means of retroreflecting material.
(3) Subject to sub-paragraph (4), the parts of the roundel coloured yellow must be either fluorescent or illuminated by means of internal lighting.
(4) Subject to sub-paragraph (5) with the exception of the parts of the roundel coloured black and any protective strip applied to the perimeter of the roundel, the roundel must be illuminated by means of retroreflecting material and any such material applied to the parts coloured yellow must, if not fluorescent, be applied in horizontal strips with gaps between the strips.
(5) The parts of the roundel coloured red may be fluorescent or illuminated by means of internal lighting.