Administratum Grey vs Light Blue RLM78

How close are they?

ΔE 7.8, close: similar, with a visible difference side by side. Light Blue RLM78 is more saturated than Administratum Grey.

Can I use Light Blue RLM78 instead of Administratum Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Light Blue RLM78 is more saturated than Administratum Grey.

Can I use Administratum Grey instead of Light Blue RLM78?

The same difference applies the other way round: Administratum Grey is more muted.

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.