Necron Compound vs Interference Red (Fine)

How close are they?

ΔE 34.2, loose: different enough that you should pick on purpose. Interference Red (Fine) is noticeably lighter than Necron Compound. They are different kinds of paint: Citadel Necron Compound is a metallic and Golden Interference Red (Fine) is a pearl paint, so they won’t behave the same on the model even where the colour is close.

Can I use Interference Red (Fine) instead of Necron Compound?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 34). Interference Red (Fine) is noticeably lighter than Necron Compound. They are different kinds of paint.

Can I use Necron Compound instead of Interference Red (Fine)?

The same difference applies the other way round: Necron Compound is noticeably darker.

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.