Dreadful Visage vs Undead Dragon

How close are they?

ΔE 11.2, fair: the same colour family, but not a straight swap. Undead Dragon is a little lighter, cooler than Dreadful Visage.

Can I use Undead Dragon instead of Dreadful Visage?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Undead Dragon is a little lighter, cooler than Dreadful Visage.

Can I use Dreadful Visage instead of Undead Dragon?

The same difference applies the other way round: Dreadful Visage 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.