Ushabti Bone vs Parchment

How close are they?

ΔE 8.7, close: similar, with a visible difference side by side. Parchment is a little lighter, warmer than Ushabti Bone.

Can I use Parchment instead of Ushabti Bone?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Parchment is a little lighter, warmer than Ushabti Bone.

Can I use Ushabti Bone instead of Parchment?

The same difference applies the other way round: Ushabti Bone is a little darker, cooler.

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.