ΔE 6.7, close: similar, with a visible difference side by side. Inktense Olive is a little darker, warmer than Dark Drab. They are different kinds of paint: Army Painter Dark Drab is an opaque base/layer paint and Scale75 Inktense Olive is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Inktense Olive is a little darker, warmer than Dark Drab. They are different kinds of paint.
The same difference applies the other way round: Dark Drab is a little lighter, 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 Dark Drab on the colour wheel See Inktense Olive on the colour wheel
All matches: Dark Drab equivalents · Inktense Olive equivalents