Diabolic Plum vs Dioxazine Violet

How close are they?

ΔE 9.2, close: similar, with a visible difference side by side. Dioxazine Violet is a little darker than Diabolic Plum.

Can I use Dioxazine Violet instead of Diabolic Plum?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Dioxazine Violet is a little darker than Diabolic Plum.

Can I use Diabolic Plum instead of Dioxazine Violet?

The same difference applies the other way round: Diabolic Plum is a little lighter.

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.