Pine Hollow Shade vs Aether Blue

How close are they?

ΔE 37.2, loose: different enough that you should pick on purpose. Aether Blue is noticeably lighter, more saturated than Pine Hollow Shade.

Can I use Aether Blue instead of Pine Hollow Shade?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 37). Aether Blue is noticeably lighter, more saturated than Pine Hollow Shade.

Can I use Pine Hollow Shade instead of Aether Blue?

The same difference applies the other way round: Pine Hollow Shade is noticeably darker, 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.