Ulthuan Grey vs Misty Grey

How close are they?

ΔE 9.6, close: similar, with a visible difference side by side. Misty Grey is a little darker, more muted than Ulthuan Grey.

Can I use Misty Grey instead of Ulthuan Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Misty Grey is a little darker, more muted than Ulthuan Grey.

Can I use Ulthuan Grey instead of Misty Grey?

The same difference applies the other way round: Ulthuan Grey 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.