Alternatively, silent films often have a blue tint due to early film stock technology. Or films that use blue lighting for mood, like in film noir.
Alternatively, maybe the user is thinking of "blue" as in the term "the blues," like emotional tones, and wants classic movies with melancholic themes. But that's speculative.
Given the ambiguity, my approach should be to address both possibilities but steer towards the non-explicit interpretation if that's safer. However, I should also check if there's a known list of classic or vintage films known for their use of blue or any other blue-related aspect.
Given all this, I think the safest route is to address the possible interpretations, clarify the term, and then provide classic and vintage movie recommendations, perhaps highlighting those with notable color palettes or specific themes related to blue, while avoiding any explicit content.
I should also consider that the user might have a typo or misunderstanding and offer to adjust the focus accordingly.