Caledor Sky vs Thunder Blue

How close are they?

ΔE 9.8, close: similar, with a visible difference side by side. Thunder Blue is a little lighter, more saturated, warmer than Caledor Sky.

Can I use Thunder Blue instead of Caledor Sky?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Thunder Blue is a little lighter, more saturated, warmer than Caledor Sky.

Can I use Caledor Sky instead of Thunder Blue?

The same difference applies the other way round: Caledor Sky is a little darker, 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.