Familiar Pink vs Fire Red

How close are they?

ΔE 39.4, loose: different enough that you should pick on purpose. Fire Red is noticeably darker, much more muted, warmer than Familiar Pink. They are different kinds of paint: Army Painter Familiar Pink is a one-coat contrast-style paint and Reaper Fire Red is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.

Can I use Fire Red instead of Familiar Pink?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 39). Fire Red is noticeably darker, much more muted, warmer than Familiar Pink. They are different kinds of paint.

Can I use Familiar Pink instead of Fire Red?

The same difference applies the other way round: Familiar Pink is noticeably lighter, much more saturated, 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.