Cygnar Blue Base vs Andrea Blue

How close are they?

ΔE 27.6, loose: different enough that you should pick on purpose. Andrea Blue is noticeably lighter, much more muted, cooler than Cygnar Blue Base.

Can I use Andrea Blue instead of Cygnar Blue Base?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 28). Andrea Blue is noticeably lighter, much more muted, cooler than Cygnar Blue Base.

Can I use Cygnar Blue Base instead of Andrea Blue?

The same difference applies the other way round: Cygnar Blue Base is noticeably darker, much more saturated, 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.