Snow Blue vs Neptune Glow

How close are they?

ΔE 15.4, loose: different enough that you should pick on purpose. Neptune Glow is a little darker, more saturated, cooler than Snow Blue.

Can I use Neptune Glow instead of Snow Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Neptune Glow is a little darker, more saturated, cooler than Snow Blue.

Can I use Snow Blue instead of Neptune Glow?

The same difference applies the other way round: Snow Blue is a little lighter, more muted, warmer.

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.