ΔE 5.5, very close: most people won’t see a difference side by side. Intense Brown is a little lighter than Rust Tone. They are different kinds of paint: Army Painter Rust Tone is a wash/shade and Reaper Intense Brown is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Yes, for most jobs. Very close match (ΔE 5). Intense Brown is a little lighter than Rust Tone. They are different kinds of paint.
The same difference applies the other way round: Rust Tone is a little darker.
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.
See Rust Tone on the colour wheel See Intense Brown on the colour wheel
All matches: Rust Tone equivalents · Intense Brown equivalents