Skorne Red vs Sanctuary Red

How close are they?

ΔE 26.4, loose: different enough that you should pick on purpose. Sanctuary Red is noticeably lighter, much more saturated than Skorne Red.

Can I use Sanctuary Red instead of Skorne Red?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Sanctuary Red is noticeably lighter, much more saturated than Skorne Red.

Can I use Skorne Red instead of Sanctuary Red?

The same difference applies the other way round: Skorne Red is noticeably darker, much 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.