ΔE 9.8, close: similar, with a visible difference side by side. Brilliant Blue is a little lighter, cooler than Calgar Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Brilliant Blue is a little lighter, cooler than Calgar Blue.
The same difference applies the other way round: Calgar Blue is a little darker, 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.
See Calgar Blue on the colour wheel See Brilliant Blue on the colour wheel
All matches: Calgar Blue equivalents · Brilliant Blue equivalents