Dark Wood vs Russet Brown

How close are they?

ΔE 7.2, close: similar, with a visible difference side by side. Russet Brown is a little darker, cooler than Dark Wood. They are different kinds of paint: Army Painter Dark Wood is a one-coat contrast-style paint and Reaper Russet Brown is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.

Can I use Russet Brown instead of Dark Wood?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Russet Brown is a little darker, cooler than Dark Wood. They are different kinds of paint.

Can I use Dark Wood instead of Russet Brown?

The same difference applies the other way round: Dark Wood is a little lighter, 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.