"coloured" instead? This way, it is at least not connoted to America.  But it is a bit strange trying to avoid the past participle of a regular verb.  Moreover, there is no way to misunderstand the use in this case.  I doubt that this kind of PC helps anyone.  But I am not an American and may be looking at it from the wrong perspective.  On the other hand, our perspectives are all narrow.  Many words we use in a technical sense may be difficult in certain situations in certain cultures we don't think of.