Plate Mail Metal vs Radiant Platinum

How close are they?

ΔE 17.8, loose: different enough that you should pick on purpose. Radiant Platinum is a little lighter, more saturated than Plate Mail Metal.

Can I use Radiant Platinum instead of Plate Mail Metal?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Radiant Platinum is a little lighter, more saturated than Plate Mail Metal.

Can I use Plate Mail Metal instead of Radiant Platinum?

The same difference applies the other way round: Plate Mail Metal is a little darker, 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.