ΔE 8.9, close: similar, with a visible difference side by side. Flat Red is more saturated, warmer than Emperor Red.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Flat Red is more saturated, warmer than Emperor Red.
The same difference applies the other way round: Emperor Red is more muted, 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 Emperor Red on the colour wheel See Flat Red on the colour wheel
All matches: Emperor Red equivalents · Flat Red equivalents