Luminous Flesh vs Hearthborn

How close are they?

ΔE 7.7, close: similar, with a visible difference side by side. Hearthborn is warmer than Luminous Flesh.

Can I use Hearthborn instead of Luminous Flesh?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Hearthborn is warmer than Luminous Flesh.

Can I use Luminous Flesh instead of Hearthborn?

The same difference applies the other way round: Luminous Flesh is 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.