ΔE 15.0, fair: the same colour family, but not a straight swap. Ivory is a little lighter, much more muted than Pallid Bone. They are different kinds of paint: Army Painter Pallid Bone is a one-coat contrast-style paint and Vallejo Ivory is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
✓ Herrick Games paint comparison chart lists these two as equivalents.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Ivory is a little lighter, much more muted than Pallid Bone. They are different kinds of paint.
The same difference applies the other way round: Pallid Bone is a little darker, much 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 Pallid Bone on the colour wheel See Ivory on the colour wheel
All matches: Pallid Bone equivalents · Ivory equivalents