Celestial Blue vs Elfic Blue

How close are they?

ΔE 7.7, close: similar, with a visible difference side by side. Elfic Blue is a little lighter than Celestial Blue.

Can I use Elfic Blue instead of Celestial Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Elfic Blue is a little lighter than Celestial Blue.

Can I use Celestial Blue instead of Elfic Blue?

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

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.