ΔE 9.4, close: similar, with a visible difference side by side. Transparent Blue is a little darker, more saturated, warmer than Soulstone Blue. They are different kinds of paint: Citadel Soulstone Blue is a technical paint or medium and Pro Acryl Transparent Blue 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). Transparent Blue is a little darker, more saturated, warmer than Soulstone Blue. They are different kinds of paint.
The same difference applies the other way round: Soulstone Blue is a little lighter, 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 Soulstone Blue on the colour wheel See Transparent Blue on the colour wheel
All matches: Soulstone Blue equivalents · Transparent Blue equivalents