Iron Warriors vs Black Metal

How close are they?

ΔE 16.4, loose: different enough that you should pick on purpose. Black Metal is noticeably darker, more muted than Iron Warriors.

Can I use Black Metal instead of Iron Warriors?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Black Metal is noticeably darker, more muted than Iron Warriors.

Can I use Iron Warriors instead of Black Metal?

The same difference applies the other way round: Iron Warriors is noticeably lighter, 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.