Is the "indigo" stripe of the rainbow more blue or violet?

[dtilque]

@themapleleaf

In actual fact, is there any substantial red content in the “indigo” stripe, which would make it a shade of violet/purple (or at least “blue-violet”, I.E. the tertiary color), or is it really a more or less pure blue? Has this even been determined scientifically, or is it purely a matter of perception? Is it more of a gradient? I.E., is the “indigo” stripe actually part blue and part violet?

The red pigment in the eye has a small amount of reaction to deep blue/violet wavelengths. So they look purplish, even though they don’t have any actual red color.