Gelbbraun 8020 vs Barren Dune

How close are they?

ΔE 8.7, close: similar, with a visible difference side by side. Barren Dune is a little darker, more muted than Gelbbraun 8020.

Can I use Barren Dune instead of Gelbbraun 8020?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Barren Dune is a little darker, more muted than Gelbbraun 8020.

Can I use Gelbbraun 8020 instead of Barren Dune?

The same difference applies the other way round: Gelbbraun 8020 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.