Calgar Blue vs Blue Ink

How close are they?

ΔE 12.9, fair: the same colour family, but not a straight swap. Blue Ink is a little lighter, warmer than Calgar Blue. They are different kinds of paint: Citadel Calgar Blue is an opaque base/layer paint and Formula P3 Blue Ink is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.

Can I use Blue Ink instead of Calgar Blue?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Blue Ink is a little lighter, warmer than Calgar Blue. They are different kinds of paint.

Can I use Calgar Blue instead of Blue Ink?

The same difference applies the other way round: Calgar Blue is a little darker, 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.