Omega Blue vs Mica Blue

How close are they?

ΔE 15.4, loose: different enough that you should pick on purpose. Mica Blue is a little lighter, much more saturated, warmer than Omega Blue.

Can I use Mica Blue instead of Omega Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Mica Blue is a little lighter, much more saturated, warmer than Omega Blue.

Can I use Omega Blue instead of Mica Blue?

The same difference applies the other way round: Omega Blue is a little darker, 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.