ΔE 8.6, close: similar, with a visible difference side by side. Tenebris Blue is a little lighter, warmer than Highlord Blue. They are different kinds of paint: Army Painter Highlord Blue is a one-coat contrast-style paint and Green Stuff World Tenebris Blue 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 9). Tenebris Blue is a little lighter, warmer than Highlord Blue. They are different kinds of paint.
The same difference applies the other way round: Highlord Blue is a little darker, 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 Highlord Blue on the colour wheel See Tenebris Blue on the colour wheel
All matches: Highlord Blue equivalents · Tenebris Blue equivalents