True Brass vs Dark Iron

How close are they?

ΔE 24.1, loose: different enough that you should pick on purpose. Dark Iron is noticeably darker, more muted, warmer than True Brass.

Can I use Dark Iron instead of True Brass?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Dark Iron is noticeably darker, more muted, warmer than True Brass.

Can I use True Brass instead of Dark Iron?

The same difference applies the other way round: True Brass is noticeably lighter, more saturated, 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.