Frost Blue vs Glazier Blue

How close are they?

ΔE 8.5, close: similar, with a visible difference side by side. Glazier Blue is a little lighter, warmer than Frost Blue.

Can I use Glazier Blue instead of Frost Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Glazier Blue is a little lighter, warmer than Frost Blue.

Can I use Frost Blue instead of Glazier Blue?

The same difference applies the other way round: Frost Blue is a little darker, cooler.

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.