Dryad Brown vs Ruddy Leather

How close are they?

ΔE 6.5, close: similar, with a visible difference side by side. Ruddy Leather is more muted, cooler than Dryad Brown.

Can I use Ruddy Leather instead of Dryad Brown?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Ruddy Leather is more muted, cooler than Dryad Brown.

Can I use Dryad Brown instead of Ruddy Leather?

The same difference applies the other way round: Dryad Brown is more saturated, 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.