ΔE 10.8, fair: the same colour family, but not a straight swap. Ink Sepia is a little lighter, more saturated than Black Ink.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Ink Sepia is a little lighter, more saturated than Black Ink.
The same difference applies the other way round: Black Ink is a little darker, 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 Black Ink on the colour wheel See Ink Sepia on the colour wheel
All matches: Black Ink equivalents · Ink Sepia equivalents