Dark Imperial Khaki vs Bastion Grey

How close are they?

ΔE 8.8, close: similar, with a visible difference side by side. Bastion Grey is a little darker, warmer than Dark Imperial Khaki.

Can I use Bastion Grey instead of Dark Imperial Khaki?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Bastion Grey is a little darker, warmer than Dark Imperial Khaki.

Can I use Dark Imperial Khaki instead of Bastion Grey?

The same difference applies the other way round: Dark Imperial Khaki is a little lighter, 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.