Imperial Red vs Bloody Red

How close are they?

ΔE 9.7, close: similar, with a visible difference side by side. Bloody Red is a little darker, more saturated than Imperial Red.

Can I use Bloody Red instead of Imperial Red?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Bloody Red is a little darker, more saturated than Imperial Red.

Can I use Imperial Red instead of Bloody Red?

The same difference applies the other way round: Imperial Red is a little lighter, more muted.

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.