ΔE 12.6, fair: the same colour family, but not a straight swap. Rakarth Flesh is noticeably lighter, warmer than Matt Starship Filth. They are different kinds of paint: AMMO by Mig Matt Starship Filth is an ink, glaze or transparent paint and Citadel Rakarth Flesh 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 13). Rakarth Flesh is noticeably lighter, warmer than Matt Starship Filth. They are different kinds of paint.
The same difference applies the other way round: Matt Starship Filth is noticeably darker, 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 Matt Starship Filth on the colour wheel See Rakarth Flesh on the colour wheel
All matches: Matt Starship Filth equivalents · Rakarth Flesh equivalents