Martian Ironcrust vs Endurance Brown

How close are they?

ΔE 7.1, close: similar, with a visible difference side by side. Endurance Brown is warmer than Martian Ironcrust. They are different kinds of paint: Citadel Martian Ironcrust is a technical paint or medium and Scale75 Endurance Brown is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.

Can I use Endurance Brown instead of Martian Ironcrust?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Endurance Brown is warmer than Martian Ironcrust. They are different kinds of paint.

Can I use Martian Ironcrust instead of Endurance Brown?

The same difference applies the other way round: Martian Ironcrust is 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.