Angelic Red vs Carnage Red

How close are they?

ΔE 23.9, loose: different enough that you should pick on purpose. Carnage Red is noticeably darker, much more muted than Angelic Red.

Can I use Carnage Red instead of Angelic Red?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Carnage Red is noticeably darker, much more muted than Angelic Red.

Can I use Angelic Red instead of Carnage Red?

The same difference applies the other way round: Angelic Red is noticeably lighter, much 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.