ΔE 12.4, fair: the same colour family, but not a straight swap. Dirty Grey is a little darker, more muted, cooler than Dune Shadow.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Dirty Grey is a little darker, more muted, cooler than Dune Shadow.
The same difference applies the other way round: Dune Shadow is a little lighter, more saturated, warmer.
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 Dune Shadow on the colour wheel See Dirty Grey on the colour wheel
All matches: Dune Shadow equivalents · Dirty Grey equivalents