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