RLM 63 vs Dawnstone

How close are they?

ΔE 9.7, close: similar, with a visible difference side by side. Dawnstone is a little darker, more muted than RLM 63.

Can I use Dawnstone instead of RLM 63?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Dawnstone is a little darker, more muted than RLM 63.

Can I use RLM 63 instead of Dawnstone?

The same difference applies the other way round: RLM 63 is a little lighter, more saturated.

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.