Reddish Flesh vs Elder Flower

How close are they?

ΔE 16.3, loose: different enough that you should pick on purpose. Elder Flower is a little lighter, much more saturated, cooler than Reddish Flesh.

Can I use Elder Flower instead of Reddish Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Elder Flower is a little lighter, much more saturated, cooler than Reddish Flesh.

Can I use Reddish Flesh instead of Elder Flower?

The same difference applies the other way round: Reddish Flesh is a little darker, much 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.