Phthalo Turquoise Light vs Russian AF Grey N.7

How close are they?

ΔE 7.4, close: similar, with a visible difference side by side. Russian AF Grey N.7 is a little lighter than Phthalo Turquoise Light.

Can I use Russian AF Grey N.7 instead of Phthalo Turquoise Light?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Russian AF Grey N.7 is a little lighter than Phthalo Turquoise Light.

Can I use Phthalo Turquoise Light instead of Russian AF Grey N.7?

The same difference applies the other way round: Phthalo Turquoise Light is a little darker.

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.