Anthrax Metal vs Old Gold

How close are they?

ΔE 38.3, loose: different enough that you should pick on purpose. Old Gold is noticeably darker, much more saturated than Anthrax Metal.

Can I use Old Gold instead of Anthrax Metal?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 38). Old Gold is noticeably darker, much more saturated than Anthrax Metal.

Can I use Anthrax Metal instead of Old Gold?

The same difference applies the other way round: Anthrax Metal is noticeably lighter, much 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.