ΔE 5.3, very close: most people won’t see a difference side by side. OSL White is a little darker, more muted than Wrack White. They are different kinds of paint: Citadel Wrack White is an opaque base/layer paint and Green Stuff World OSL White 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 5). OSL White is a little darker, more muted than Wrack White. They are different kinds of paint.
The same difference applies the other way round: Wrack White is a little lighter, more saturated.
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 Wrack White on the colour wheel See OSL White on the colour wheel
All matches: Wrack White equivalents · OSL White equivalents