Q: B&W tint changes

Just watched the May 18th showing on TCM off my DVR. During the first several minutes of the film the tint of the B&W film kept changing - seemingly almost from shot to shot - from strict black and white to a more bluish-gray and back again. Does this have something to do with the original filmstock used, the print, or was it something with the broadcast or even my LCD TV?

I've seen this before in a couple other old B&W films and my guess it's the print - being cobbled together from at least two to get the cleanest version possible to show or put on DVD today.