Longbeard Grey vs Russian AF Grey N.4

How close are they?

ΔE 11.5, fair: the same colour family, but not a straight swap. Russian AF Grey N.4 is a little darker, more saturated than Longbeard Grey.

Can I use Russian AF Grey N.4 instead of Longbeard Grey?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Russian AF Grey N.4 is a little darker, more saturated than Longbeard Grey.

Can I use Longbeard Grey instead of Russian AF Grey N.4?

The same difference applies the other way round: Longbeard Grey is a little lighter, 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.