ΔE 7.1, close: similar, with a visible difference side by side. Scarlet Blood is a little lighter than Pyrrole Red Dark.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Scarlet Blood is a little lighter than Pyrrole Red Dark.
The same difference applies the other way round: Pyrrole Red Dark is a little darker.
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 Pyrrole Red Dark on the colour wheel See Scarlet Blood on the colour wheel
All matches: Pyrrole Red Dark equivalents · Scarlet Blood equivalents