Field Grey vs Grey Green

How close are they?

ΔE 9.1, close: similar, with a visible difference side by side. Grey Green is a little darker, more muted than Field Grey.

Can I use Grey Green instead of Field Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Grey Green is a little darker, more muted than Field Grey.

Can I use Field Grey instead of Grey Green?

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