Luminous Flesh vs Ungor Flesh

How close are they?

ΔE 15.0, loose: different enough that you should pick on purpose. Ungor Flesh is noticeably darker, more saturated than Luminous Flesh.

Can I use Ungor Flesh instead of Luminous Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Ungor Flesh is noticeably darker, more saturated than Luminous Flesh.

Can I use Luminous Flesh instead of Ungor Flesh?

The same difference applies the other way round: Luminous Flesh is noticeably lighter, more muted.

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.