Blue Licks vs Alien Purple

How close are they?

ΔE 25.4, loose: different enough that you should pick on purpose. Alien Purple is noticeably darker, more muted, warmer than Blue Licks.

Can I use Alien Purple instead of Blue Licks?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Alien Purple is noticeably darker, more muted, warmer than Blue Licks.

Can I use Blue Licks instead of Alien Purple?

The same difference applies the other way round: Blue Licks is noticeably lighter, 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.