Intermediate Blue vs Thunderous Blue

How close are they?

ΔE 8.0, close: similar, with a visible difference side by side. Thunderous Blue is more saturated, cooler than Intermediate Blue.

Can I use Thunderous Blue instead of Intermediate Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Thunderous Blue is more saturated, cooler than Intermediate Blue.

Can I use Intermediate Blue instead of Thunderous Blue?

The same difference applies the other way round: Intermediate 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.