Mechanicus Standard Grey vs Dark Green BS641

How close are they?

ΔE 10.5, fair: the same colour family, but not a straight swap. Dark Green BS641 is a little darker than Mechanicus Standard Grey.

Can I use Dark Green BS641 instead of Mechanicus Standard Grey?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Dark Green BS641 is a little darker than Mechanicus Standard Grey.

Can I use Mechanicus Standard Grey instead of Dark Green BS641?

The same difference applies the other way round: Mechanicus Standard Grey is a little lighter.

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.