ΔE 8.9, close: similar, with a visible difference side by side. Warlord Purple is more saturated, warmer than Purple Alchemy. They are different kinds of paint: Army Painter Purple Alchemy is a one-coat contrast-style paint and Vallejo Warlord Purple is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
✓ Herrick Games paint comparison chart lists these two as equivalents.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Warlord Purple is more saturated, warmer than Purple Alchemy. They are different kinds of paint.
The same difference applies the other way round: Purple Alchemy is 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.
See Purple Alchemy on the colour wheel See Warlord Purple on the colour wheel
All matches: Purple Alchemy equivalents · Warlord Purple equivalents