ΔE 9.4, close: similar, with a visible difference side by side. AMT-12 Dark Grey is a little darker, more saturated than Slate Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). AMT-12 Dark Grey is a little darker, more saturated than Slate Grey.
The same difference applies the other way round: Slate Grey is a little lighter, more muted.
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 Slate Grey on the colour wheel See AMT-12 Dark Grey on the colour wheel
All matches: Slate Grey equivalents · AMT-12 Dark Grey equivalents