ΔE 9.5, close: similar, with a visible difference side by side. Cerulean Blue Hue is a little lighter, more saturated than Ultramarines Blue. They are different kinds of paint: Citadel Ultramarines Blue is a one-coat contrast-style paint and Golden Cerulean Blue Hue 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). Cerulean Blue Hue is a little lighter, more saturated than Ultramarines Blue. They are different kinds of paint.
The same difference applies the other way round: Ultramarines Blue is a little darker, more muted.
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 Ultramarines Blue on the colour wheel See Cerulean Blue Hue on the colour wheel
All matches: Ultramarines Blue equivalents · Cerulean Blue Hue equivalents