Dark Nude Pink vs Elder Flower

How close are they?

ΔE 17.4, loose: different enough that you should pick on purpose. Elder Flower is noticeably darker, more saturated, cooler than Dark Nude Pink.

Can I use Elder Flower instead of Dark Nude Pink?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Elder Flower is noticeably darker, more saturated, cooler than Dark Nude Pink.

Can I use Dark Nude Pink instead of Elder Flower?

The same difference applies the other way round: Dark Nude Pink is noticeably lighter, more muted, 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.