Thunderous Blue vs Cerulean Blue Deep

How close are they?

ΔE 15.0, fair: the same colour family, but not a straight swap. Cerulean Blue Deep is a little darker, more saturated, warmer than Thunderous Blue.

Can I use Cerulean Blue Deep instead of Thunderous Blue?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Cerulean Blue Deep is a little darker, more saturated, warmer than Thunderous Blue.

Can I use Thunderous Blue instead of Cerulean Blue Deep?

The same difference applies the other way round: Thunderous Blue is a little lighter, more muted, 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.