Liberator Gold vs Radium

How close are they?

ΔE 15.9, loose: different enough that you should pick on purpose. Radium is noticeably lighter, more muted than Liberator Gold.

Can I use Radium instead of Liberator Gold?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Radium is noticeably lighter, more muted than Liberator Gold.

Can I use Liberator Gold instead of Radium?

The same difference applies the other way round: Liberator Gold is noticeably darker, 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.