ΔE 42.0, loose: different enough that you should pick on purpose. Archaic Sepia Wash is noticeably lighter, much more muted, cooler than Seraphim Sepia.
✓ Two Thin Coats comparison chart lists these two as equivalents.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 42). Archaic Sepia Wash is noticeably lighter, much more muted, cooler than Seraphim Sepia.
The same difference applies the other way round: Seraphim Sepia is noticeably darker, much more saturated, 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 Seraphim Sepia on the colour wheel See Archaic Sepia Wash on the colour wheel
All matches: Seraphim Sepia equivalents · Archaic Sepia Wash equivalents