Ocean Depths vs Dark Emerald

How close are they?

ΔE 15.7, loose: different enough that you should pick on purpose. Dark Emerald is a little darker, more muted, warmer than Ocean Depths.

Can I use Dark Emerald instead of Ocean Depths?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Dark Emerald is a little darker, more muted, warmer than Ocean Depths.

Can I use Ocean Depths instead of Dark Emerald?

The same difference applies the other way round: Ocean Depths is a little lighter, more saturated, 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.