ΔE 9.5, close: similar, with a visible difference side by side. Majestic Fortress is a little lighter, cooler than Dark Green INK. They are different kinds of paint: AK Interactive Dark Green INK is an ink, glaze or transparent paint and Army Painter Majestic Fortress is an opaque base/layer 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 10). Majestic Fortress is a little lighter, cooler than Dark Green INK. They are different kinds of paint.
The same difference applies the other way round: Dark Green INK is a little darker, warmer.
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 Green INK on the colour wheel See Majestic Fortress on the colour wheel
All matches: Dark Green INK equivalents · Majestic Fortress equivalents