The copper one on “Fringe” looked cool.
I think they used the copper from the old Bell Labs Murray Hill building as it was approximately the same age,and hence had the same coloration.
My father is an architect, and used copper in many of his buildings built in the 1950s-70s at a local college. None of it has turned green–it’s all remained a deep brown. Unfortunately, by the time my brother and I thought to ask him why, he couldn’t remember if it was somehow treated, and he’d been retired long enough that his firm’s records weren’t around to check the specifications. I also notice that a green copper roof on a local basilica was famously replaced some years ago, and the new copper roof remains the same deep brown. It makes me think that commonly used roofing or construction “copper” may be an alloy, or is treated in some other way. But that’s sheer speculation.
copper forms a protective brown oxide very rapidly.
Wikipedia has a good sized Copper in Architecture article with a fair amount on this.
Are there any known color photos of it when it was copper? (I do believe color photography existed at the time)
patina can be everything from green to red…
Cite? I never saw it down to the copper color and I can assure you I was in the area during the time. As far as I know the only stripping that was done happened to the interior. In fact the exterior scaffolding was entirely aluminum so that there would be no rust to stain the outside patina.