Stratos Blue vs Sentient Turquoise

How close are they?

ΔE 15.1, loose: different enough that you should pick on purpose. Sentient Turquoise is noticeably lighter, cooler than Stratos Blue.

Can I use Sentient Turquoise instead of Stratos Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Sentient Turquoise is noticeably lighter, cooler than Stratos Blue.

Can I use Stratos Blue instead of Sentient Turquoise?

The same difference applies the other way round: Stratos Blue is noticeably darker, 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.