ΔE 7.5, close: similar, with a visible difference side by side. Celestra Grey is a little lighter than Matt Night Blue. They are different kinds of paint: AMMO by Mig Matt Night Blue is an ink, glaze or transparent paint and Citadel Celestra Grey 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 7). Celestra Grey is a little lighter than Matt Night Blue. They are different kinds of paint.
The same difference applies the other way round: Matt Night Blue is a little darker.
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 Matt Night Blue on the colour wheel See Celestra Grey on the colour wheel
All matches: Matt Night Blue equivalents · Celestra Grey equivalents