One way they could have done "tinted" B&W would be to play the B&W footage in a color telecine, and misadjust the color balance. Cut back on the blue, and increase the red a little, and you would get a tinted video stream. You could change the tint for various scenes, say yellowish for outdoor sunlit scenes, blueish for rainy days, pink for lovers kissing (this is terrestrial broadcast of course
) and so on.