Hi, I do not understand the question?
Glow in the dark is also expensive, why wate the effect with white ink?
We use glow in the dark because a glow effect is required.
Glow in the dark is a powder pigment, so more ink means in proportion less glow in the dark pigment. Also the wite is the most opaque color, so it cut the effect in a significant way. Cured white as base (so it does not merge with the pigment) will enanche the glow effect.