OHMYGOD I LOVE THIS MOVIE/SONG/ALBUM. AHHH. Ok so the movie is very colourful, the song is amazing, and the album is actually quite great with the songs then the George Martin orchestra songs.
Mkay lemme explain. So what Beatle fans know, the Yellow Submarine song was recorded and released in 1966 in the Revolver album. The Revolver album was literally like... the drug album but Yellow Submarine was one out of the very few songs on that album that wasn't inspired by drugs. And so well the year they were creating the movie was 1967 which was the year of "love" and "psychedelia" so that ment colours and all that creative stuff. So look at the art, colours right? Yeah.