ΔE 16.2, loose: different enough that you should pick on purpose. IDF Gray 1 (-1981 Sinai) is noticeably darker, more saturated, warmer than Screaming Skull.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). IDF Gray 1 (-1981 Sinai) is noticeably darker, more saturated, warmer than Screaming Skull.
The same difference applies the other way round: Screaming Skull is noticeably 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 Screaming Skull on the colour wheel See IDF Gray 1 (-1981 Sinai) on the colour wheel
All matches: Screaming Skull equivalents · IDF Gray 1 (-1981 Sinai) equivalents