ΔE 6.8, close: similar, with a visible difference side by side. Sepia is more saturated, warmer than Dark Battle Dress. They are different kinds of paint: Army Painter Dark Battle Dress is an opaque base/layer paint and Golden Sepia 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). Sepia is more saturated, warmer than Dark Battle Dress. They are different kinds of paint.
The same difference applies the other way round: Dark Battle Dress is more muted, 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 Battle Dress on the colour wheel See Sepia on the colour wheel
All matches: Dark Battle Dress equivalents · Sepia equivalents