ΔE 13.9, fair: the same colour family, but not a straight swap. Stonewall Grey is noticeably lighter than Griffon Claw.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Stonewall Grey is noticeably lighter than Griffon Claw.
The same difference applies the other way round: Griffon Claw is noticeably darker.
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 Griffon Claw on the colour wheel See Stonewall Grey on the colour wheel
All matches: Griffon Claw equivalents · Stonewall Grey equivalents