The first-level illusionist spell color spray operates by overloading the senses/neural networks of its subject. My Dungeon Master rules that the same lack of conventional consciousness that makes the undead immune to sleep and charm also makes them immune to color spray. Do you agree?

This is a by-the-book First Edition AD&D game (PHB, DMG, no orange spines allowed).

The first-level illusionist spell color spray operates by overloading the senses/neural networks of its subject. Our view is that the same lack of conventional consciousness that makes the undead immune to sleep and charm also makes them immune to color spray. Would love to hear different interpretations, or assent.

This is a by-the-book First Edition AD&D game (PHB, DMG, no orange spines allowed).