ΔE 19.0, loose: different enough that you should pick on purpose. Deep Scarlet Ink is noticeably darker, cooler than Screamer Pink. They are different kinds of paint: Citadel Screamer Pink is an opaque base/layer paint and Nocturna Models Deep Scarlet Ink is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Deep Scarlet Ink is noticeably darker, cooler than Screamer Pink. They are different kinds of paint.
The same difference applies the other way round: Screamer Pink is noticeably lighter, warmer.
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 Screamer Pink on the colour wheel See Deep Scarlet Ink on the colour wheel
All matches: Screamer Pink equivalents · Deep Scarlet Ink equivalents