Barren Yellow vs Manticore Ochre

How close are they?

ΔE 21.0, loose: different enough that you should pick on purpose. Manticore Ochre is noticeably lighter, more saturated, cooler than Barren Yellow.

Can I use Manticore Ochre instead of Barren Yellow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Manticore Ochre is noticeably lighter, more saturated, cooler than Barren Yellow.

Can I use Barren Yellow instead of Manticore Ochre?

The same difference applies the other way round: Barren Yellow is noticeably darker, more muted, 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.