ΔE 14.7, fair: the same colour family, but not a straight swap. Titan Buff is noticeably lighter than Wraithbone. They are different kinds of paint: Citadel Wraithbone is an opaque base/layer paint and Golden Titan Buff is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Titan Buff is noticeably lighter than Wraithbone. They are different kinds of paint.
The same difference applies the other way round: Wraithbone is noticeably darker.
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 Wraithbone on the colour wheel See Titan Buff on the colour wheel
All matches: Wraithbone equivalents · Titan Buff equivalents