Washable Dust vs Karak Stone

How close are they?

ΔE 7.1, close: similar, with a visible difference side by side. Karak Stone is a little lighter than Washable Dust.

Can I use Karak Stone instead of Washable Dust?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Karak Stone is a little lighter than Washable Dust.

Can I use Washable Dust instead of Karak Stone?

The same difference applies the other way round: Washable Dust is a little darker.

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.