Psychic Shock vs Bright Green Blue

How close are they?

ΔE 17.0, loose: different enough that you should pick on purpose. Bright Green Blue is a little lighter, much more muted, warmer than Psychic Shock.

Can I use Bright Green Blue instead of Psychic Shock?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Bright Green Blue is a little lighter, much more muted, warmer than Psychic Shock.

Can I use Psychic Shock instead of Bright Green Blue?

The same difference applies the other way round: Psychic Shock is a little darker, much 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.