Grimoire Purple vs Gal Vorbak Red

How close are they?

ΔE 15.2, loose: different enough that you should pick on purpose. Gal Vorbak Red is a little darker, more saturated, warmer than Grimoire Purple.

Can I use Gal Vorbak Red instead of Grimoire Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Gal Vorbak Red is a little darker, more saturated, warmer than Grimoire Purple.

Can I use Grimoire Purple instead of Gal Vorbak Red?

The same difference applies the other way round: Grimoire Purple is a little lighter, more muted, 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.