Dark Blue-Grey vs Evergreen Fog

How close are they?

ΔE 7.2, close: similar, with a visible difference side by side. Evergreen Fog is a little lighter, more saturated, cooler than Dark Blue-Grey.

Can I use Evergreen Fog instead of Dark Blue-Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Evergreen Fog is a little lighter, more saturated, cooler than Dark Blue-Grey.

Can I use Dark Blue-Grey instead of Evergreen Fog?

The same difference applies the other way round: Dark Blue-Grey is a little darker, more muted, 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.