Plaguebearer Flesh vs Bag of Bones

How close are they?

ΔE 18.7, loose: different enough that you should pick on purpose. Bag of Bones is noticeably darker, warmer than Plaguebearer Flesh.

Can I use Bag of Bones instead of Plaguebearer Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Bag of Bones is noticeably darker, warmer than Plaguebearer Flesh.

Can I use Plaguebearer Flesh instead of Bag of Bones?

The same difference applies the other way round: Plaguebearer Flesh is noticeably lighter, 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.