Gobi Brown vs Green Yellow

How close are they?

ΔE 8.1, close: similar, with a visible difference side by side. Green Yellow is more muted, cooler than Gobi Brown.

Can I use Green Yellow instead of Gobi Brown?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Green Yellow is more muted, cooler than Gobi Brown.

Can I use Gobi Brown instead of Green Yellow?

The same difference applies the other way round: Gobi Brown is more saturated, 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.