Grey Shadow vs Mahogany Brown

How close are they?

ΔE 8.9, close: similar, with a visible difference side by side. Mahogany Brown is a little darker, more saturated, warmer than Grey Shadow.

Can I use Mahogany Brown instead of Grey Shadow?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Mahogany Brown is a little darker, more saturated, warmer than Grey Shadow.

Can I use Grey Shadow instead of Mahogany Brown?

The same difference applies the other way round: Grey Shadow is a little lighter, more muted, cooler.

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.