Chaotic Red vs Oxide Brown Dark

How close are they?

ΔE 9.2, close: similar, with a visible difference side by side. Oxide Brown Dark is a little darker, warmer than Chaotic Red.

Can I use Oxide Brown Dark instead of Chaotic Red?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Oxide Brown Dark is a little darker, warmer than Chaotic Red.

Can I use Chaotic Red instead of Oxide Brown Dark?

The same difference applies the other way round: Chaotic Red is a little lighter, 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.