Just been looking at junction boxes and conduit to move an external PIR floodlight. Why is it that most junction boxes are grey but conduit only comes in black or white?

I was thinking that black would be less obvious than white, but I havent seen any black junction boxes. Grey wouldnt be too bad but I havent seen any grey conduit.

Am I missing something?

I think having different colours would just look like I was using up stuff that I had laying around in the shed rather than specifically buying stuff for the job.

Alan