Plate Mail Metal vs Necron Compound

How close are they?

ΔE 8.2, close: similar, with a visible difference side by side. Necron Compound is a little darker than Plate Mail Metal.

Can I use Necron Compound instead of Plate Mail Metal?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Necron Compound is a little darker than Plate Mail Metal.

Can I use Plate Mail Metal instead of Necron Compound?

The same difference applies the other way round: Plate Mail Metal is a little lighter.

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.