Imp Yellow vs Hawkshroud Yellow

How close are they?

ΔE 9.4, close: similar, with a visible difference side by side. Hawkshroud Yellow is a little lighter, cooler than Imp Yellow.

Can I use Hawkshroud Yellow instead of Imp Yellow?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Hawkshroud Yellow is a little lighter, cooler than Imp Yellow.

Can I use Imp Yellow instead of Hawkshroud Yellow?

The same difference applies the other way round: Imp Yellow is a little darker, 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.