Catachan Flesh vs Bootstrap Leather

How close are they?

ΔE 8.6, close: similar, with a visible difference side by side. Bootstrap Leather is more saturated, cooler than Catachan Flesh.

Can I use Bootstrap Leather instead of Catachan Flesh?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Bootstrap Leather is more saturated, cooler than Catachan Flesh.

Can I use Catachan Flesh instead of Bootstrap Leather?

The same difference applies the other way round: Catachan Flesh is more muted, 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.