ΔE 14.1, fair: the same colour family, but not a straight swap. Red Ink is noticeably lighter, more muted than Poppy Red. They are different kinds of paint: Army Painter Poppy Red is a one-coat contrast-style paint and Formula P3 Red Ink is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Red Ink is noticeably lighter, more muted than Poppy Red. They are different kinds of paint.
The same difference applies the other way round: Poppy Red is noticeably darker, more saturated.
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.
See Poppy Red on the colour wheel See Red Ink on the colour wheel
All matches: Poppy Red equivalents · Red Ink equivalents