Violet Grey vs Sombre Grey

How close are they?

ΔE 7.9, close: similar, with a visible difference side by side. Sombre Grey is more muted, cooler than Violet Grey.

Can I use Sombre Grey instead of Violet Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Sombre Grey is more muted, cooler than Violet Grey.

Can I use Violet Grey instead of Sombre Grey?

The same difference applies the other way round: Violet Grey is more saturated, 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.