Night Blue vs Ink Dark Turquoise

How close are they?

ΔE 20.0, loose: different enough that you should pick on purpose. Ink Dark Turquoise is a little darker, more muted, warmer than Night Blue.

Can I use Ink Dark Turquoise instead of Night Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Ink Dark Turquoise is a little darker, more muted, warmer than Night Blue.

Can I use Night Blue instead of Ink Dark Turquoise?

The same difference applies the other way round: Night Blue is a little 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.