And for reference there's a section in this BBC film about how it was done in the 1970s, by hand: https://www.bbc.co.uk/programmes/p01z4rrj https://www.bbc.co.u

And for reference there's a section in this BBC film about how it was done in the 1970s, by hand: https://www.bbc.co.uk/programmes/p01z4rrj https://www.bbc.co.uk/programmes/p01z4rrj