Sky Blue vs Phalanx Blue

How close are they?

ΔE 8.7, close: similar, with a visible difference side by side. Phalanx Blue is more saturated, cooler than Sky Blue.

Can I use Phalanx Blue instead of Sky Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Phalanx Blue is more saturated, cooler than Sky Blue.

Can I use Sky Blue instead of Phalanx Blue?

The same difference applies the other way round: Sky Blue is more muted, 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.