Cobalt Metal vs Metallic Blue

How close are they?

ΔE 32.1, loose: different enough that you should pick on purpose. Metallic Blue is much more saturated, warmer than Cobalt Metal.

Can I use Metallic Blue instead of Cobalt Metal?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 32). Metallic Blue is much more saturated, warmer than Cobalt Metal.

Can I use Cobalt Metal instead of Metallic Blue?

The same difference applies the other way round: Cobalt Metal is much more muted, 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.