ΔE 7.3, close: similar, with a visible difference side by side. Macragge Blue is a little darker than Altdorf Guard Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Macragge Blue is a little darker than Altdorf Guard Blue.
The same difference applies the other way round: Altdorf Guard Blue is a little lighter.
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 Altdorf Guard Blue on the colour wheel See Macragge Blue on the colour wheel
All matches: Altdorf Guard Blue equivalents · Macragge Blue equivalents