Dusty Skull vs Dragon Fang

How close are they?

ΔE 6.6, close: similar, with a visible difference side by side. Dragon Fang is more saturated, warmer than Dusty Skull.

Can I use Dragon Fang instead of Dusty Skull?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Dragon Fang is more saturated, warmer than Dusty Skull.

Can I use Dusty Skull instead of Dragon Fang?

The same difference applies the other way round: Dusty Skull is 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.