Aztec Gold vs Brass Balls

How close are they?

ΔE 44.4, loose: different enough that you should pick on purpose. Brass Balls is noticeably lighter, much more muted than Aztec Gold.

Can I use Brass Balls instead of Aztec Gold?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 44). Brass Balls is noticeably lighter, much more muted than Aztec Gold.

Can I use Aztec Gold instead of Brass Balls?

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