Polished Bone vs Silver Grey

How close are they?

ΔE 7.5, close: similar, with a visible difference side by side. Silver Grey is a little darker, more muted, warmer than Polished Bone.

Can I use Silver Grey instead of Polished Bone?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Silver Grey is a little darker, more muted, warmer than Polished Bone.

Can I use Polished Bone instead of Silver Grey?

The same difference applies the other way round: Polished Bone is a little lighter, more saturated, 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.