Alaitoc Blue vs Summersea Blue

How close are they?

ΔE 16.4, loose: different enough that you should pick on purpose. Summersea Blue is much more saturated, warmer than Alaitoc Blue.

Can I use Summersea Blue instead of Alaitoc Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Summersea Blue is much more saturated, warmer than Alaitoc Blue.

Can I use Alaitoc Blue instead of Summersea Blue?

The same difference applies the other way round: Alaitoc Blue is much 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.