Cloudburst Blue vs Asurmen Blue

How close are they?

ΔE 18.2, loose: different enough that you should pick on purpose. Asurmen Blue is much more saturated, cooler than Cloudburst Blue.

Can I use Asurmen Blue instead of Cloudburst Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Asurmen Blue is much more saturated, cooler than Cloudburst Blue.

Can I use Cloudburst Blue instead of Asurmen Blue?

The same difference applies the other way round: Cloudburst Blue is much more muted, 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.