ΔE 9.7, close: similar, with a visible difference side by side. Turquoise (Phthalo) is a little darker, more saturated, warmer than Dark Reaper. They are different kinds of paint: Citadel Dark Reaper is an opaque base/layer paint and Golden Turquoise (Phthalo) is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Turquoise (Phthalo) is a little darker, more saturated, warmer than Dark Reaper. They are different kinds of paint.
The same difference applies the other way round: Dark Reaper is a little lighter, more muted, 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.
See Dark Reaper on the colour wheel See Turquoise (Phthalo) on the colour wheel
All matches: Dark Reaper equivalents · Turquoise (Phthalo) equivalents