White Hat History anyone?

[WhistlesAndStripes]

OK, I was having a discussion with a co-worker of mine today in regards to Ron Jaworski replacing Joe THeismann on the Monday night football broadcast crew. As we got to talking about how horrible Joe is in the booth, I mentioned the play where his leg got broken. My co-worker had never seen it, so we went and looked it up on YouTube.

As the play ends, the first official on the field to enter the picture was wearing a white hat, but appeared to come from the defensive side of the field, so I thought it was odd that he would be wearing a white hat. So much so, that I watched it again to see if there was any way that the Referee could have come in from that angle. This time, I watched the clip all the way to the end, and at the end of the clip, you could see most of the officials huddled to talk about something, and they were ALL wearing white hats.

So, I'm curious to know when football crews went from ALL wearing white hats to just the Referee wearing them.