ΔE 9.3, close: similar, with a visible difference side by side. Siena is more saturated, warmer than Dusk Red. They are different kinds of paint: Army Painter Dusk Red is a one-coat contrast-style paint and Green Stuff World Siena is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Siena is more saturated, warmer than Dusk Red. They are different kinds of paint.
The same difference applies the other way round: Dusk Red 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 Dusk Red on the colour wheel See Siena on the colour wheel
All matches: Dusk Red equivalents · Siena equivalents