Tyrian Navy vs Dusty Blue

How close are they?

ΔE 7.5, close: similar, with a visible difference side by side. Dusty Blue is a little lighter, more saturated, cooler than Tyrian Navy.

Can I use Dusty Blue instead of Tyrian Navy?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Dusty Blue is a little lighter, more saturated, cooler than Tyrian Navy.

Can I use Tyrian Navy instead of Dusty Blue?

The same difference applies the other way round: Tyrian Navy is a little darker, more muted, 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.