Zephyr Pink vs Shell Shocked

How close are they?

ΔE 22.3, loose: different enough that you should pick on purpose. Shell Shocked is noticeably darker, more muted, cooler than Zephyr Pink.

Can I use Shell Shocked instead of Zephyr Pink?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Shell Shocked is noticeably darker, more muted, cooler than Zephyr Pink.

Can I use Zephyr Pink instead of Shell Shocked?

The same difference applies the other way round: Zephyr Pink is noticeably lighter, more saturated, warmer.

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.