Light Feldgrau vs Grey Teal

How close are they?

ΔE 6.6, close: similar, with a visible difference side by side. Grey Teal is a little darker, cooler than Light Feldgrau.

Can I use Grey Teal instead of Light Feldgrau?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Grey Teal is a little darker, cooler than Light Feldgrau.

Can I use Light Feldgrau instead of Grey Teal?

The same difference applies the other way round: Light Feldgrau is a little lighter, 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.