Field Grey vs Medieval Forest

How close are they?

ΔE 9.8, close: similar, with a visible difference side by side. Medieval Forest is a little lighter, more saturated, cooler than Field Grey.

Can I use Medieval Forest instead of Field Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Medieval Forest is a little lighter, more saturated, cooler than Field Grey.

Can I use Field Grey instead of Medieval Forest?

The same difference applies the other way round: Field 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.