Green vs Ink Dark Turquoise

How close are they?

ΔE 42.7, loose: different enough that you should pick on purpose. Ink Dark Turquoise is noticeably darker, much more muted, cooler than Green.

Can I use Ink Dark Turquoise instead of Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 43). Ink Dark Turquoise is noticeably darker, much more muted, cooler than Green.

Can I use Green instead of Ink Dark Turquoise?

The same difference applies the other way round: Green is noticeably lighter, much more saturated, warmer.

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.