Sylvaneth Bark vs Bastion Grey

How close are they?

ΔE 19.1, loose: different enough that you should pick on purpose. Bastion Grey is a little lighter, more muted, cooler than Sylvaneth Bark.

Can I use Bastion Grey instead of Sylvaneth Bark?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Bastion Grey is a little lighter, more muted, cooler than Sylvaneth Bark.

Can I use Sylvaneth Bark instead of Bastion Grey?

The same difference applies the other way round: Sylvaneth Bark is a little darker, more saturated, warmer.

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.