Ivory White vs Titan Green Pale

How close are they?

ΔE 17.3, loose: different enough that you should pick on purpose. Titan Green Pale is a little darker, more muted, cooler than Ivory White.

Can I use Titan Green Pale instead of Ivory White?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Titan Green Pale is a little darker, more muted, cooler than Ivory White.

Can I use Ivory White instead of Titan Green Pale?

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