Templar Blue vs Dark Blue RLM24

How close are they?

ΔE 8.3, close: similar, with a visible difference side by side. Dark Blue RLM24 is more saturated, warmer than Templar Blue.

Can I use Dark Blue RLM24 instead of Templar Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Dark Blue RLM24 is more saturated, warmer than Templar Blue.

Can I use Templar Blue instead of Dark Blue RLM24?

The same difference applies the other way round: Templar Blue is 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.