Royal Purple vs Shell Shocked

How close are they?

ΔE 22.2, loose: different enough that you should pick on purpose. Shell Shocked is noticeably lighter, much more muted, warmer than Royal Purple.

Can I use Shell Shocked instead of Royal Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Shell Shocked is noticeably lighter, much more muted, warmer than Royal Purple.

Can I use Royal Purple instead of Shell Shocked?

The same difference applies the other way round: Royal Purple is noticeably darker, much more saturated, 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.