ΔE 13.0, fair: the same colour family, but not a straight swap. Umber Wash is a little lighter, more saturated than Black Wash.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Umber Wash is a little lighter, more saturated than Black Wash.
The same difference applies the other way round: Black Wash is a little darker, more muted.
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 Black Wash on the colour wheel See Umber Wash on the colour wheel
All matches: Black Wash equivalents · Umber Wash equivalents