Fenrisian Grey vs Artic Blue

How close are they?

ΔE 16.2, loose: different enough that you should pick on purpose. Artic Blue is noticeably lighter, more muted than Fenrisian Grey.

Can I use Artic Blue instead of Fenrisian Grey?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Artic Blue is noticeably lighter, more muted than Fenrisian Grey.

Can I use Fenrisian Grey instead of Artic Blue?

The same difference applies the other way round: Fenrisian Grey is noticeably darker, more saturated.

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.