Brownish Decay vs Orc Skin

How close are they?

ΔE 23.7, loose: different enough that you should pick on purpose. Orc Skin is a little lighter, more saturated, cooler than Brownish Decay.

Can I use Orc Skin instead of Brownish Decay?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Orc Skin is a little lighter, more saturated, cooler than Brownish Decay.

Can I use Brownish Decay instead of Orc Skin?

The same difference applies the other way round: Brownish Decay is a little darker, 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.