Ash Grey vs Gravestone Blue

How close are they?

ΔE 9.8, close: similar, with a visible difference side by side. Gravestone Blue is a little darker, more saturated than Ash Grey.

Can I use Gravestone Blue instead of Ash Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Gravestone Blue is a little darker, more saturated than Ash Grey.

Can I use Ash Grey instead of Gravestone Blue?

The same difference applies the other way round: Ash Grey is a little 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.