ΔE 25.1, loose: different enough that you should pick on purpose. Dark Vermilion is much more saturated, cooler than Dull Red.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Dark Vermilion is much more saturated, cooler than Dull Red.
The same difference applies the other way round: Dull Red is much more muted, warmer.
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 Dull Red on the colour wheel See Dark Vermilion on the colour wheel
All matches: Dull Red equivalents · Dark Vermilion equivalents