Soulblight Grey vs Andalusian Earth

How close are they?

ΔE 23.2, loose: different enough that you should pick on purpose. Andalusian Earth is noticeably darker, more saturated than Soulblight Grey.

Can I use Andalusian Earth instead of Soulblight Grey?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Andalusian Earth is noticeably darker, more saturated than Soulblight Grey.

Can I use Soulblight Grey instead of Andalusian Earth?

The same difference applies the other way round: Soulblight Grey is noticeably lighter, more muted.

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.