Re: How many prints were floating round in the 1960s...?
Yeah, for most of the 35mm prints they were output direct from the cameras. Don't ask me how it differed from the 16mm telerecordings, or how Planet of Giants 3 was made (which the video off the quad tapes was transferred to 35mm).
Might ask the RT.
"I'd rather be judged by twelve than carried by six."