Astral Beryllium vs Cobalt Metal

How close are they?

ΔE 16.3, loose: different enough that you should pick on purpose. Cobalt Metal is a little darker, cooler than Astral Beryllium.

Can I use Cobalt Metal instead of Astral Beryllium?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Cobalt Metal is a little darker, cooler than Astral Beryllium.

Can I use Astral Beryllium instead of Cobalt Metal?

The same difference applies the other way round: Astral Beryllium is a little lighter, 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.