Impish Rouge vs Quinacridone Magenta

How close are they?

ΔE 19.7, loose: different enough that you should pick on purpose. Quinacridone Magenta is noticeably darker, more muted than Impish Rouge.

Can I use Quinacridone Magenta instead of Impish Rouge?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Quinacridone Magenta is noticeably darker, more muted than Impish Rouge.

Can I use Impish Rouge instead of Quinacridone Magenta?

The same difference applies the other way round: Impish Rouge is noticeably lighter, more saturated.

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.