ΔE 9.2, close: similar, with a visible difference side by side. Phthalo Blue RS is a little darker, warmer than Macragge Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Phthalo Blue RS is a little darker, warmer than Macragge Blue.
The same difference applies the other way round: Macragge Blue is a little lighter, 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.
See Macragge Blue on the colour wheel See Phthalo Blue RS on the colour wheel
All matches: Macragge Blue equivalents · Phthalo Blue RS equivalents