ΔE 5.6, very close: most people won’t see a difference side by side. Our swatches for the two are almost the same. They are different kinds of paint: Citadel Dryad Bark is an opaque base/layer paint and Green Stuff World Opulentus Black is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Yes, for most jobs. Very close match (ΔE 6). The swatches are almost the same. They are different kinds of paint.
The same difference applies the other way round.
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.
See Dryad Bark on the colour wheel See Opulentus Black on the colour wheel
All matches: Dryad Bark equivalents · Opulentus Black equivalents