Quoted from CrazyLevi:Pretty sure this predates blue screen (green screen came in for digital).
On those old movies they just rear projected on a big screen, which is why it generally looks so terrible.
I think people forgot about 'blue screens'..Although I can't say they were using blue screens on these particular films, but they were popular..GREEN SCREENS..yeah these are used 24/7 on video-shot material. I'd have to ask my buddy who used to work at Lucas Films, Robert Zemecis, etc. Industial Light and Magic's last 'backdrop' (hand painted backdrop about 15 feet wide, by 7 ft tall) was the last shot of Die Hard 2, at the tarmac as the credits start rolling..I saw that in person..kinda funny, as it totally fooled me on LD, DVD..probably can't fool on 4K though. And the last 'model' that ILM did was a decently-sized USS Protector, from Galaxy Quest...two distinct ends of one badass era. I MISS MODELS>..."Real Mechs".