Early 20th Century Posters: Colours!

1 - 2 - 3

4 - 5 - 6

I picked some existing Sci Fi movie posters to analyse the colours of, as I'm leaning towards using this design style in my own poster. 

There's yellow in every single one of these posters, just at different degrees of use. 2 of these posters also have very similar colour scheme - numbers 2 and 4 ("I married a monster from outer space" and "Mothra".) Red, black and yellow, with a off-white border. Red, black and yellow together are a good combination as they all contrast against each other very well. Red and black are bright and bold colours that catch attention.

Each colour that's used in the posters is used in quite a large, obvious block and nothing is coloured so that it appears subtle or not noticed as much.