Bad Bruise vs Hexed Lichen

How close are they?

ΔE 27.9, loose: different enough that you should pick on purpose. Hexed Lichen is noticeably lighter, much more saturated than Bad Bruise.

Can I use Hexed Lichen instead of Bad Bruise?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 28). Hexed Lichen is noticeably lighter, much more saturated than Bad Bruise.

Can I use Bad Bruise instead of Hexed Lichen?

The same difference applies the other way round: Bad Bruise is noticeably darker, much more muted.

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.