ΔE 9.6, close: similar, with a visible difference side by side. Royal Blue is a little darker, more muted than Soulstone Blue. They are different kinds of paint: Citadel Soulstone Blue is a technical paint or medium and Vallejo Royal Blue is an opaque base/layer 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 10). Royal Blue is a little darker, more muted than Soulstone Blue. They are different kinds of paint.
The same difference applies the other way round: Soulstone Blue is a little lighter, more saturated.
ΔE is the colour difference between our two swatch estimates: under 2 is a perfect match (you’d struggle to tell them apart), under 6 very close, under 10 close, under 15 fair, under 20 loose, under 30 very loose, and 30 or more a poor match. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Soulstone Blue on the colour wheel See Royal Blue on the colour wheel
All matches: Soulstone Blue equivalents · Royal Blue equivalents