Neptune's Fury vs Blueberry

How close are they?

ΔE 18.1, loose: different enough that you should pick on purpose. Blueberry is a little darker, more muted, warmer than Neptune's Fury.

Can I use Blueberry instead of Neptune's Fury?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Blueberry is a little darker, more muted, warmer than Neptune's Fury.

Can I use Neptune's Fury instead of Blueberry?

The same difference applies the other way round: Neptune's Fury is a little lighter, more saturated, 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.