Barren Yellow vs Half-Orc Highlight

How close are they?

ΔE 10.0, close: similar, with a visible difference side by side. Half-Orc Highlight is a little darker, more muted than Barren Yellow.

Can I use Half-Orc Highlight instead of Barren Yellow?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Half-Orc Highlight is a little darker, more muted than Barren Yellow.

Can I use Barren Yellow instead of Half-Orc Highlight?

The same difference applies the other way round: Barren Yellow 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.