Opal Skin vs Titan Violet Pale

How close are they?

ΔE 16.0, loose: different enough that you should pick on purpose. Titan Violet Pale is a little lighter, more muted than Opal Skin.

Can I use Titan Violet Pale instead of Opal Skin?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Titan Violet Pale is a little lighter, more muted than Opal Skin.

Can I use Opal Skin instead of Titan Violet Pale?

The same difference applies the other way round: Opal Skin is a little darker, more saturated.

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.