I have been watching an occasional old film on 81 (Talking Pictures).

This morning there was a short BFI B&W kids film on (The Christmas
Tree), from 1966, with kids involved in journey taking a Christmas tree
to London. Rather oddly and despite it being a B&W film, the tree's
foliage showed up quite faintly as green. None of the grass, nor the
other trees showed as even slightly green. All rather puzzling, but I
remember a TV experiment from way back, where they tested B&W TV's to
hint at showing some colour. Anyone remember it?

I like watching some of these older low budget films, for the quiet
roads and vehicles from the early days of my motoring career.