Raging Rose vs C.P. Cadmium Red Dark

How close are they?

ΔE 20.7, loose: different enough that you should pick on purpose. C.P. Cadmium Red Dark is noticeably darker, more saturated than Raging Rose.

Can I use C.P. Cadmium Red Dark instead of Raging Rose?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). C.P. Cadmium Red Dark is noticeably darker, more saturated than Raging Rose.

Can I use Raging Rose instead of C.P. Cadmium Red Dark?

The same difference applies the other way round: Raging Rose is noticeably lighter, 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.