Barren Dune vs Yellow Ochre

How close are they?

ΔE 23.9, loose: different enough that you should pick on purpose. Yellow Ochre is noticeably darker, much more saturated, warmer than Barren Dune.

Can I use Yellow Ochre instead of Barren Dune?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Yellow Ochre is noticeably darker, much more saturated, warmer than Barren Dune.

Can I use Barren Dune instead of Yellow Ochre?

The same difference applies the other way round: Barren Dune is noticeably lighter, much more muted, 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.