ΔE 10.3, fair: the same colour family, but not a straight swap. Brown RLM26 is a little lighter than Amethyst Rose.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Brown RLM26 is a little lighter than Amethyst Rose.
The same difference applies the other way round: Amethyst Rose is a little 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.
See Amethyst Rose on the colour wheel See Brown RLM26 on the colour wheel
All matches: Amethyst Rose equivalents · Brown RLM26 equivalents