T'au Light Ochre vs Vulcan Orange

How close are they?

ΔE 13.9, fair: the same colour family, but not a straight swap. Vulcan Orange is noticeably darker, warmer than T'au Light Ochre.

Can I use Vulcan Orange instead of T'au Light Ochre?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Vulcan Orange is noticeably darker, warmer than T'au Light Ochre.

Can I use T'au Light Ochre instead of Vulcan Orange?

The same difference applies the other way round: T'au Light Ochre is noticeably 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.