Ultramarine Blue vs Caledor Sky

How close are they?

ΔE 10.7, fair: the same colour family, but not a straight swap. Caledor Sky is a little lighter, cooler than Ultramarine Blue.

Can I use Caledor Sky instead of Ultramarine Blue?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Caledor Sky is a little lighter, cooler than Ultramarine Blue.

Can I use Ultramarine Blue instead of Caledor Sky?

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

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.