Russet Shadow vs Thondia Brown

How close are they?

ΔE 9.1, close: similar, with a visible difference side by side. Thondia Brown is more saturated, warmer than Russet Shadow.

Can I use Thondia Brown instead of Russet Shadow?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Thondia Brown is more saturated, warmer than Russet Shadow.

Can I use Russet Shadow instead of Thondia Brown?

The same difference applies the other way round: Russet Shadow is 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.