Bloodreaver Flesh vs Red Rage

How close are they?

ΔE 7.9, close: similar, with a visible difference side by side. Red Rage is a little darker, more muted than Bloodreaver Flesh.

Can I use Red Rage instead of Bloodreaver Flesh?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Red Rage is a little darker, more muted than Bloodreaver Flesh.

Can I use Bloodreaver Flesh instead of Red Rage?

The same difference applies the other way round: Bloodreaver Flesh is a little lighter, more saturated.

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.