You are right, Eng 123, I expressed myself the wrong way.
What I meant is that if the ground engineer only reports smoke and nothing more, that's not an excuse for the captain not to take the initiative to ask for more details.
If somebody shouts smoke, the captain is supposed to take the lead in closing the communication loop.
I had in mind the Tenerife accident, in which the PanAm crew was feeling very unconfortable while backtracking, but instead of relying on minimal and difficult communications, why the hell the Captain didn't grab the mike to talk directly to the KLM Captain??
Anyway, now we know that's not exactly what happened in Sydney, so my question regarding the colour of the smoke has only a generic sense.
See you soon... LEM