Tarnished Steel vs Dark Gunmetal

How close are they?

ΔE 12.7, fair: the same colour family, but not a straight swap. Dark Gunmetal is noticeably lighter than Tarnished Steel.

Can I use Dark Gunmetal instead of Tarnished Steel?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Dark Gunmetal is noticeably lighter than Tarnished Steel.

Can I use Tarnished Steel instead of Dark Gunmetal?

The same difference applies the other way round: Tarnished Steel is noticeably darker.

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.