Runic Cobalt vs Celestra Grey

How close are they?

ΔE 8.7, close: similar, with a visible difference side by side. Celestra Grey is more muted, cooler than Runic Cobalt.

Can I use Celestra Grey instead of Runic Cobalt?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Celestra Grey is more muted, cooler than Runic Cobalt.

Can I use Runic Cobalt instead of Celestra Grey?

The same difference applies the other way round: Runic Cobalt is 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.