Greenish White vs Pallid Wych Flesh

How close are they?

ΔE 16.5, loose: different enough that you should pick on purpose. Pallid Wych Flesh is noticeably darker, more muted, warmer than Greenish White.

Can I use Pallid Wych Flesh instead of Greenish White?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Pallid Wych Flesh is noticeably darker, more muted, warmer than Greenish White.

Can I use Greenish White instead of Pallid Wych Flesh?

The same difference applies the other way round: Greenish White is noticeably 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.