Braunviolett RLM 81 vs Grape Red

How close are they?

ΔE 7.8, close: similar, with a visible difference side by side. Grape Red is a little darker, more saturated, cooler than Braunviolett RLM 81.

Can I use Grape Red instead of Braunviolett RLM 81?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Grape Red is a little darker, more saturated, cooler than Braunviolett RLM 81.

Can I use Braunviolett RLM 81 instead of Grape Red?

The same difference applies the other way round: Braunviolett RLM 81 is a little lighter, more muted, 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.