RAL 1039 F9 Sandbeige vs US Earth Yellow

How close are they?

ΔE 7.1, close: similar, with a visible difference side by side. US Earth Yellow is a little darker, warmer than RAL 1039 F9 Sandbeige.

Can I use US Earth Yellow instead of RAL 1039 F9 Sandbeige?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). US Earth Yellow is a little darker, warmer than RAL 1039 F9 Sandbeige.

Can I use RAL 1039 F9 Sandbeige instead of US Earth Yellow?

The same difference applies the other way round: RAL 1039 F9 Sandbeige is a little lighter, cooler.

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.