Battleship Grey vs Dark Turquoise

How close are they?

ΔE 30.5, loose: different enough that you should pick on purpose. Dark Turquoise is noticeably darker, more saturated, warmer than Battleship Grey.

Can I use Dark Turquoise instead of Battleship Grey?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Dark Turquoise is noticeably darker, more saturated, warmer than Battleship Grey.

Can I use Battleship Grey instead of Dark Turquoise?

The same difference applies the other way round: Battleship Grey is noticeably lighter, more muted, 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.