Gauss Blaster Green vs Arcane Blue

How close are they?

ΔE 15.3, loose: different enough that you should pick on purpose. Arcane Blue is a little lighter, cooler than Gauss Blaster Green.

Can I use Arcane Blue instead of Gauss Blaster Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Arcane Blue is a little lighter, cooler than Gauss Blaster Green.

Can I use Gauss Blaster Green instead of Arcane Blue?

The same difference applies the other way round: Gauss Blaster Green is a little darker, 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.