As adjectives the difference between blank and empty is that blank is without color; lacking characteristics which give variety while empty is devoid of content; containing nothing or nobody; vacant.
As nouns the difference between blank and empty is that blank is a cartridge that is designed to simulate the noise and smoke of real gunfire without actually firing a projectile while empty is a container, especially a bottle, whose contents have been used up, leaving it empty .
As verbs the difference between blank and empty is that blank is to make void; to erase while empty is (ergative) to make empty; to void; to remove the contents of.