ΔE 13.3, fair: the same colour family, but not a straight swap. Raw Umber is a little lighter, more saturated, warmer than Stirland Mud.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Raw Umber is a little lighter, more saturated, warmer than Stirland Mud.
The same difference applies the other way round: Stirland Mud is a little darker, more muted, 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.
See Stirland Mud on the colour wheel See Raw Umber on the colour wheel
All matches: Stirland Mud equivalents · Raw Umber equivalents