ΔE 11.9, fair: the same colour family, but not a straight swap. Acid Pink is a little lighter, more saturated than Doomfire Magenta. They are different kinds of paint: Citadel Doomfire Magenta is a one-coat contrast-style paint and Scale75 Acid Pink is a fluorescent or effect 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 12). Acid Pink is a little lighter, more saturated than Doomfire Magenta. They are different kinds of paint.
The same difference applies the other way round: Doomfire Magenta is a little darker, 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.
See Doomfire Magenta on the colour wheel See Acid Pink on the colour wheel
All matches: Doomfire Magenta equivalents · Acid Pink equivalents