Colourless reflex reflectors must not produce a selective reflection; that is to say, the trichromatic coordinates "x" and "y" of the standard illuminant A used to illuminate the reflex reflector must not undergo a change of more than 0 701 after reflection by the reflex reflector.
3.1. This shall be verified by the visual comparison test indicated in 2.1 the control field being illuminated by a light source of which the trichromatic coordinates differ by 0 701 from that of standard illuminant A.
