ΔE 10.5, fair: the same colour family, but not a straight swap. Dark Grey RLM42 is more muted than Dark Reaper.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Dark Grey RLM42 is more muted than Dark Reaper.
The same difference applies the other way round: Dark Reaper is 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.
See Dark Reaper on the colour wheel See Dark Grey RLM42 on the colour wheel
All matches: Dark Reaper equivalents · Dark Grey RLM42 equivalents