Calgar Blue vs Tenebris Blue

How close are they?

ΔE 9.5, close: similar, with a visible difference side by side. Tenebris Blue is more muted, warmer than Calgar Blue. They are different kinds of paint: Citadel Calgar Blue is an opaque base/layer paint and Green Stuff World Tenebris Blue 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 Tenebris Blue instead of Calgar Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Tenebris Blue is more muted, warmer than Calgar Blue. They are different kinds of paint.

Can I use Calgar Blue instead of Tenebris Blue?

The same difference applies the other way round: Calgar Blue is more saturated, 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.