Rust Brown vs Brown RLM26

How close are they?

ΔE 12.1, fair: the same colour family, but not a straight swap. Brown RLM26 is noticeably darker, more muted than Rust Brown.

Can I use Brown RLM26 instead of Rust Brown?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Brown RLM26 is noticeably darker, more muted than Rust Brown.

Can I use Rust Brown instead of Brown RLM26?

The same difference applies the other way round: Rust Brown 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.