Russ Grey vs UK Azure Blue

How close are they?

ΔE 7.2, close: similar, with a visible difference side by side. UK Azure Blue is a little lighter, warmer than Russ Grey.

Can I use UK Azure Blue instead of Russ Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). UK Azure Blue is a little lighter, warmer than Russ Grey.

Can I use Russ Grey instead of UK Azure Blue?

The same difference applies the other way round: Russ Grey is a little darker, cooler.

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.