ΔE 9.4, close: similar, with a visible difference side by side. Scarlet Blood is a little darker, more saturated than Sun Red.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Scarlet Blood is a little darker, more saturated than Sun Red.
The same difference applies the other way round: Sun Red is a little lighter, 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 Sun Red on the colour wheel See Scarlet Blood on the colour wheel
All matches: Sun Red equivalents · Scarlet Blood equivalents