Copper vs Brazen Copper

How close are they?

ΔE 33.2, loose: different enough that you should pick on purpose. Brazen Copper is noticeably darker, more muted than Copper.

Can I use Brazen Copper instead of Copper?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 33). Brazen Copper is noticeably darker, more muted than Copper.

Can I use Copper instead of Brazen Copper?

The same difference applies the other way round: Copper 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.