Wasteland Soil vs Phantom Violet

How close are they?

ΔE 27.2, loose: different enough that you should pick on purpose. Phantom Violet is much more saturated, cooler than Wasteland Soil.

Can I use Phantom Violet instead of Wasteland Soil?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 27). Phantom Violet is much more saturated, cooler than Wasteland Soil.

Can I use Wasteland Soil instead of Phantom Violet?

The same difference applies the other way round: Wasteland Soil is much 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.