Pink Flesh vs Tan

How close are they?

ΔE 17.9, loose: different enough that you should pick on purpose. Tan is a little darker, much more saturated, warmer than Pink Flesh.

Can I use Tan instead of Pink Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Tan is a little darker, much more saturated, warmer than Pink Flesh.

Can I use Pink Flesh instead of Tan?

The same difference applies the other way round: Pink Flesh is a little lighter, much more muted, 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.