ΔE 10.8, fair: the same colour family, but not a straight swap. Seraphim Sepia is a little darker, more saturated, cooler than Light Clay. They are different kinds of paint: AMMO by Mig Light Clay is an ink, glaze or transparent paint and Citadel Seraphim Sepia is a wash/shade, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Seraphim Sepia is a little darker, more saturated, cooler than Light Clay. They are different kinds of paint.
The same difference applies the other way round: Light Clay is a little lighter, more muted, 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 Light Clay on the colour wheel See Seraphim Sepia on the colour wheel
All matches: Light Clay equivalents · Seraphim Sepia equivalents