Deep Azure vs Coal Black

How close are they?

ΔE 9.0, close: similar, with a visible difference side by side. Coal Black is a little darker, more muted than Deep Azure.

Can I use Coal Black instead of Deep Azure?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Coal Black is a little darker, more muted than Deep Azure.

Can I use Deep Azure instead of Coal Black?

The same difference applies the other way round: Deep Azure 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.