Ratling Grime vs Orc Skin

How close are they?

ΔE 18.1, loose: different enough that you should pick on purpose. Orc Skin is a little darker, more saturated, cooler than Ratling Grime.

Can I use Orc Skin instead of Ratling Grime?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Orc Skin is a little darker, more saturated, cooler than Ratling Grime.

Can I use Ratling Grime instead of Orc Skin?

The same difference applies the other way round: Ratling Grime is a little lighter, 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.