ΔE 20.0, loose: different enough that you should pick on purpose. Primary Magenta is noticeably darker, warmer than Impish Rouge.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Primary Magenta is noticeably darker, warmer than Impish Rouge.
The same difference applies the other way round: Impish Rouge is noticeably lighter, 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 Impish Rouge on the colour wheel See Primary Magenta on the colour wheel
All matches: Impish Rouge equivalents · Primary Magenta equivalents