Brass vs Gehenna's Gold

How close are they?

ΔE 21.0, loose: different enough that you should pick on purpose. Gehenna's Gold is noticeably darker, warmer than Brass.

Can I use Gehenna's Gold instead of Brass?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Gehenna's Gold is noticeably darker, warmer than Brass.

Can I use Brass instead of Gehenna's Gold?

The same difference applies the other way round: Brass is noticeably lighter, cooler.

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.