ΔE 13.8, fair: the same colour family, but not a straight swap. Dark Grey is noticeably lighter, more saturated than Thamar Black.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Dark Grey is noticeably lighter, more saturated than Thamar Black.
The same difference applies the other way round: Thamar Black is noticeably 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 Thamar Black on the colour wheel See Dark Grey on the colour wheel
All matches: Thamar Black equivalents · Dark Grey equivalents