Sky Blue vs Russian AF Blue

How close are they?

ΔE 7.1, close: similar, with a visible difference side by side. Russian AF Blue is more muted than Sky Blue.

Can I use Russian AF Blue instead of Sky Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Russian AF Blue is more muted than Sky Blue.

Can I use Sky Blue instead of Russian AF Blue?

The same difference applies the other way round: Sky Blue is 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.