ΔE 14.0, fair: the same colour family, but not a straight swap. Cardinal Purple is a little lighter, more saturated than Slaughter Red.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Cardinal Purple is a little lighter, more saturated than Slaughter Red.
The same difference applies the other way round: Slaughter Red is a little darker, 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 Slaughter Red on the colour wheel See Cardinal Purple on the colour wheel
All matches: Slaughter Red equivalents · Cardinal Purple equivalents