ΔE 10.2, fair: the same colour family, but not a straight swap. Crimson Hell is a little darker, cooler than Targor Rageshade. They are different kinds of paint: Citadel Targor Rageshade is a wash/shade and Nocturna Models Crimson Hell is an opaque base/layer 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 10). Crimson Hell is a little darker, cooler than Targor Rageshade. They are different kinds of paint.
The same difference applies the other way round: Targor Rageshade is a little 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 Targor Rageshade on the colour wheel See Crimson Hell on the colour wheel
All matches: Targor Rageshade equivalents · Crimson Hell equivalents