Pale Blue Dot vs Violet Vamp

How close are they?

ΔE 29.1, loose: different enough that you should pick on purpose. Violet Vamp is noticeably darker, much more muted, warmer than Pale Blue Dot.

Can I use Violet Vamp instead of Pale Blue Dot?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 29). Violet Vamp is noticeably darker, much more muted, warmer than Pale Blue Dot.

Can I use Pale Blue Dot instead of Violet Vamp?

The same difference applies the other way round: Pale Blue Dot is noticeably lighter, much more saturated, cooler.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.